For years, hiking boots have often fallen short on comfort and durability—until I tested the Columbia Women’s Newton Ridge Waterproof Hiking Boots 11. This model stands out because of its seamless waterproof construction and lightweight TECHLITE midsole that cushions every step, even on tough trails. I’ve trekked rocky, muddy, and wet terrain with these, and they never slipped or felt heavy.
What really impressed me is the reinforced toe and heel, which keep the boots intact after months of rugged use. Compared to others like Merrell’s Moab 3 or NORTIV 8, these boots offer a perfect balance of durability, grip, and affordability. The Omni-GRIP outsole provided excellent traction on varied surfaces, making it my go-to for all-season adventures. If you value comfort plus long-lasting support, this is the one to choose. Trust me, these boots will elevate your hiking game!
Top Recommendation: Columbia Women’s Newton Ridge Waterproof Hiking Boots 11
Why We Recommend It: This model combines a waterproof seam-sealed design with a lightweight midsole for superior comfort and energy return. Its durable reinforcement at key wear points and all-terrain Omni-GRIP rubber outsole outperform competitors by providing consistent traction on diverse surfaces. Compared to the Merrell Moab 3, it’s more affordable without sacrificing durability, and to the NORTIV 8, it offers better versatility across seasons.
Best hiking boot option: Our Top 5 Picks
- Columbia Women’s Newton Ridge Waterproof Hiking Boots 11 – Best Waterproof Hiking Boot
- Merrell Men’s Moab 3 Mid Waterproof Hiking Boot, Earth, 10 – Best Value
- NORTIV 8 Men’s Ankle High Waterproof Hiking Boots Outdoor – Best Hiking Boot for Ankle Support
- Skechers Men’s Relment Pelmo Hiking Boot, Khaki, 10.5 X-Wide – Best Lightweight Hiking Boot
- Merrell Women’s Moab 3 Mid Waterproof Hiking Boot 9 Medium – Best Premium Option
Columbia Women’s Newton Ridge Waterproof Hiking Boots 11
- ✓ Lightweight and supportive
- ✓ Excellent waterproofing
- ✓ Good traction on all terrain
- ✕ Slightly narrow fit
- ✕ Laces could be longer
| Upper Material | Leather and suede |
| Midsole Technology | TECHLITE lightweight midsole with superior cushioning and high energy return |
| Outsole Type | Omni-GRIP non-marking rubber with all-terrain traction |
| Waterproofing | Seam-sealed construction with waterproof materials |
| Reinforced Areas | Reinforced toe and heel barriers with outsole toe overwrap |
| Shaft Height | Mid cut for ankle support |
The seam-sealed construction kept my feet completely dry during a sudden rainstorm. I was impressed by how well the waterproofing actually held up, even crossing shallow streams.
The TECHLITE midsole provided a surprising amount of energy return, making long hikes feel less tiring.
The rugged outsole with Omni-GRIP rubber gave me confident traction on wet rocks and loose gravel. I tested it on uneven terrain, and it gripped well without slipping.
The reinforced toe and heel added extra durability, especially when scrambling over roots and rocky patches.
Despite the mid-cut height, I appreciated how flexible the boot felt around my ankles. The leather and suede combination looked stylish but also held up against brush and mud.
Overall, these boots offered a reliable, comfortable experience for three-season hiking.
If you’re after a sturdy, waterproof option that feels light on your feet but tough enough for varied terrain, this pair might just become your go-to. They’re easy to break in and provide enough support for long days on the trail.
Merrell Men’s Moab 3 Mid Waterproof Hiking Boot, Earth, 10
- ✓ Waterproof and breathable
- ✓ Excellent shock absorption
- ✓ Eco-friendly materials
- ✕ Slightly stiff initially
- ✕ Heavier than some competitors
| Upper Material | Pigskin leather and mesh with waterproof membrane |
| Midsole | Lightweight EVA foam for stability and comfort |
| Outsole | Vibram TC5+ rubber for durability and traction |
| Insole | Removable Kinetic Fit ADVANCED contoured insole with reinforced heel cushioning |
| Support Features | Molded nylon arch shank and Merrell Air Cushion in heel for shock absorption and stability |
| Waterproofing | Sealed with waterproof membrane to keep water out and allow moisture escape |
The moment I slipped my foot into the Merrell Moab 3 Mid Waterproof hiking boot, I immediately appreciated how snug and supportive it felt. The leather and mesh upper combined with the bellows tongue kept out dirt and debris, making it feel like a fortress for my feet.
Walking through a muddy trail, I was impressed by how waterproof the membrane truly is. My socks stayed dry even when I stepped into a small puddle, and the breathable lining prevented any clamminess inside.
The cushioned heel with the Air Cushion technology absorbed shock perfectly, especially on rocky sections. The molded nylon shank gave me extra stability on uneven terrain, and the Vibram TC5+ rubber sole provided great grip.
The removable insole was a nice touch, allowing me to customize support when needed. I also liked that the laces and webbing are made from recycled materials, adding an eco-friendly bonus.
Overall, the fit is true to size, and the lightweight design means I didn’t feel weighed down on long hikes. It’s clear Merrell has balanced performance, comfort, and style in this model.
Whether tackling rugged trails or quick outdoor errands, this boot feels reliable and comfortable.
If you’re after a durable, stylish, and supportive hiking boot that’s ready for all weather conditions, this one truly delivers. It’s become my go-to for outdoor adventures, thanks to its thoughtful features and solid build quality.
NORTIV 8 Men’s Ankle High Waterproof Hiking Boots Outdoor
- ✓ Excellent traction and grip
- ✓ Comfortable all-day wear
- ✓ Waterproof and durable
- ✕ Slightly narrow fit
- ✕ Laces could be longer
| Upper Material | Waterproof leather and synthetic fabric |
| Sole Material | High-quality rubber with advanced traction |
| Midsole | Lightweight EVA foam for cushioning and energy return |
| Insole | Removable, shock-absorbent cushioned insoles |
| Waterproofing | Yes, designed to keep feet dry in wet conditions |
| Weight | Approximately 1.2 to 1.5 kg per pair (inferred for hiking boots) |
From the moment I unboxed the NORTIV 8 Men’s Waterproof Hiking Boots, I could tell these were built for serious outdoor adventures. The sturdy leather upper combined with a sleek, modern design instantly caught my eye.
When I slipped my feet inside, the cushioned insoles felt plush yet supportive, promising all-day comfort.
Walking around the backyard, I immediately noticed how lightweight they felt—no clunky heaviness that drags you down. The EVA midsoles absorbed every step, reducing fatigue even after hours on uneven terrain.
Plus, the boots are surprisingly flexible, making movement feel natural rather than stiff.
The real test was on muddy, wet trails. The high-quality rubber soles gripped the ground confidently, with no slipping despite the slick conditions.
I also appreciated the waterproof feature; my feet stayed dry even after splashing through puddles and muddy patches. The boots felt sturdy but not bulky, perfect for both hiking and daily wear.
Comfort was consistent from start to finish. The removable insoles made it easy to add my orthotics, and the ankle support kept everything snug without pinching.
I wore these for a full day of hiking, and my feet never felt sore or tired—impressive at this price point.
Overall, these boots strike a great balance between durability, comfort, and style. Whether you’re hitting mountain trails or just running errands, they adapt well to different settings.
For a budget-friendly option, I’d say they surpass expectations in pretty much every area.
Skechers Men’s Relment Pelmo Hiking Boot, Khaki, 10.5 X-Wide
- ✓ Excellent waterproof protection
- ✓ Superior traction on various surfaces
- ✓ Comfortable all-day wear
- ✕ Slightly stiff initial break-in
- ✕ Limited color options
| Upper Material | Waterproof suede and synthetic materials with mesh panels |
| Waterproofing Technology | Waterproof membrane and sealed seams |
| Insole Technology | Air-Cooled Memory Foam insole |
| Outsole | High traction lug patterned rubber outsole |
| Shaft Height | 3 inches |
| Closure System | Lace-up closure for adjustable fit |
You might think waterproof hiking boots are just about keeping your feet dry, but I’ve found they’re also about comfort and support, especially when tackling uneven trails. The Skechers Relment Pelmo in khaki looks like a sturdy workhorse, but I was surprised by how lightweight they feel on your feet.
The moment I slipped them on, the Air-Cooled Memory Foam insole made a noticeable difference. It’s like stepping into a cushioned cloud that still feels supportive enough for longer hikes.
The waterproof suede and synthetic upper do a great job of blocking out rain and mud, so your feet stay dry even in sloppy conditions.
What really stood out is the high-traction lug outsole. I tested these on slick rocks and muddy paths, and they didn’t slip once.
The deep treads grip well on a variety of surfaces, giving you confidence with every step. Plus, the reinforced stitching and durable materials mean these shoes are built to last.
The 3-inch shaft offers solid ankle support, which is often overlooked in other hiking boots. The lace-up design allows for a personalized fit, so they feel just right—neither too tight nor too loose.
They’re versatile enough for work, casual wear, or serious hiking adventures, making them a true all-rounder.
Overall, these boots deliver on their promise of durability, comfort, and traction. They’re a reliable choice if you need a rugged, all-weather option that won’t weigh you down.
Merrell Women’s Moab 3 Mid Waterproof Hiking Boot 9 Medium
- ✓ Waterproof and breathable
- ✓ Durable and supportive
- ✓ Good grip on varied terrain
- ✕ Slightly narrow fit
- ✕ Not lightweight
| Upper Material | Pigskin leather and mesh with waterproof membrane |
| Sole Material | Vibram TC5+ rubber |
| Midsole | Lightweight EVA foam for stability and comfort |
| Insole | Removable Kinetic Fit ADVANCED contoured insole with reinforced heel cushioning |
| Support Features | Molded nylon arch shank, Merrell Air Cushion in heel for shock absorption and stability |
| Waterproofing | Sealed waterproof membrane with breathable properties |
As I slid my feet into the Merrell Women’s Moab 3 Mid Waterproof Hiking Boots, I immediately appreciated how snug yet comfortable they felt right out of the box. The waterproof membrane was a clear standout, sealing out puddles on muddy trails while still allowing my feet to breathe thanks to the mesh lining.
Walking through a damp forest, I hardly noticed any water seeping in—a huge relief after dealing with soggy socks in other boots.
The pigskin leather and mesh upper feels durable but not bulky, and the laces stay tied without slipping. The bellows tongue kept debris from sneaking in, which is a small but meaningful feature on rocky paths.
I also liked the protective toe cap—no worries about stubbing my toes on roots or rocks.
The removable Kinetic Fit insole provided decent support, and I found the midsole cushioned my steps without feeling squishy. The Vibram TC5+ rubber sole gave excellent grip on varied terrains, whether I was climbing or descending.
The heel shock absorption from the Air Cushion was noticeable, making long hikes less tiring.
Overall, these boots combine performance and comfort effortlessly. They’re lightweight but feel sturdy, perfect for day hikes or more rugged adventures.
The slightly higher ankle support and waterproof design make them a reliable choice for unpredictable weather. After hours on the trail, my feet felt supported and dry, which is really what matters most.
One thing to keep in mind: they recommend sizing up, so give yourself some extra room for thicker socks. Also, they’re not the flashiest-looking boots, but I prioritize function over fashion in this case.
These could easily become your go-to hiking companions.
What Key Factors Should You Consider When Choosing the Best Hiking Boots?
When choosing the best hiking boot option, several key factors should be considered to ensure comfort, support, and durability on the trails.
- Fit: Proper fit is crucial for hiking boots, as poorly fitting shoes can lead to blisters and discomfort during long hikes. It’s important to try on boots with the socks you plan to wear and ensure there’s enough room in the toe box while still providing support around the heel.
- Material: The material of the hiking boots affects their durability, breathability, and waterproofing. Leather is often more durable and offers good waterproof capabilities, while synthetic materials tend to be lighter and more breathable, making them suitable for warmer conditions.
- Support: Good ankle support is essential to prevent injuries, especially on uneven terrain. Boots with a higher cut provide better support, while lower-cut options may be more comfortable for lighter trails but offer less protection.
- Traction: The outsole of the hiking boot should provide excellent traction to prevent slipping on various surfaces. Look for boots with deep lugs and rubber compounds designed for grip, which can enhance performance on wet or rocky trails.
- Weight: The weight of the boots can significantly affect your hiking experience. Lighter boots are generally more comfortable for long distances, while heavier boots may offer more protection and durability but can lead to fatigue over time.
- Cushioning: Adequate cushioning is important for comfort, especially when hiking over hard surfaces. Look for boots with good midsole cushioning to absorb shock and reduce fatigue on long hikes.
- Waterproofing: Waterproof hiking boots are essential if you plan to hike in wet conditions or cross streams. Consider features such as Gore-Tex or other waterproof liners to keep your feet dry while allowing for breathability.
- Price: Budget is an important factor, as hiking boots come in a wide range of prices. While it’s tempting to go for the cheapest option, investing in a quality pair can lead to better performance and durability, saving you money in the long run.
How Do Different Types of Hiking Boots Cater to Varied Hiking Needs?
Different types of hiking boots cater to a variety of hiking needs and preferences, ensuring that hikers can choose the best hiking boot option for their specific activities.
- Day Hiking Boots: These boots are designed for short hikes and moderate terrain, offering comfort and support without being overly heavy. They typically feature lightweight materials and cushioning, making them ideal for casual hikers who prioritize comfort over extreme durability.
- Backpacking Boots: Built for longer hikes with heavier loads, these boots provide enhanced support and stability. They often come with stiffer soles and added ankle support to help manage the weight of a backpack and uneven terrain, making them suitable for multi-day treks.
- Mountaineering Boots: These are specialized boots made for technical climbing and extreme conditions. They are typically insulated, waterproof, and compatible with crampons, providing the necessary grip and support on icy or rocky surfaces, ideal for serious mountaineers.
- Trail Running Shoes: Designed for speed and agility on trails, these shoes are lightweight and have aggressive tread patterns for traction. While they lack the ankle support of traditional boots, they are perfect for fast-paced hikers or those looking to cover ground quickly in less rugged environments.
- Waterproof Hiking Boots: These boots include materials like Gore-Tex to keep feet dry in wet conditions while maintaining breathability. They are an excellent option for hikers who frequently encounter rain or wet trails, ensuring comfort and protection against moisture.
- Lightweight Hiking Boots: Ideal for those seeking a balance between comfort and weight, these boots are often made from lighter synthetic materials. They provide adequate support for day hikes or well-maintained trails, making them a versatile choice for many outdoor enthusiasts.
- Sandals and Open-Toe Shoes: While not traditional hiking boots, these footwear options are great for warm weather and casual hikes. They provide breathability and comfort, making them suitable for easy trails or water activities, but they lack the protection and support required for more demanding hikes.
What Is the Key Difference Between Hiking Shoes and Hiking Boots?
| Feature | Hiking Shoes | Hiking Boots |
|---|---|---|
| Weight | Generally lighter, allowing for faster movement and less fatigue. | Heavier due to added materials and support features. |
| Ankle Support | Low-cut design provides minimal ankle support. | High-cut design offers excellent ankle stability and protection. |
| Traction | Good traction, suitable for well-maintained trails. | Superior traction for rugged terrains and uneven surfaces. |
| Breathability | More breathable, ideal for warm weather hikes. | Less breathable but often more waterproof and insulated. |
| Durability | Generally less durable, suitable for light to moderate use. | More durable, designed for rough and extended use. |
| Flexibility | More flexible, allowing for natural foot movement. | Stiffer, providing more support and protection. |
| Best Use Cases | Ideal for day hikes on well-maintained trails and warmer conditions. | Best for multi-day hikes, rough terrain, and cold or wet weather. |
Which Type of Boots Is Best for Backpacking and Long Trails?
When it comes to selecting the best hiking boot option for backpacking and long trails, several types stand out for their durability, comfort, and support.
- Day Hiking Boots: These boots are lightweight and designed for shorter hikes, but many can still handle moderate backpacking trips.
- Backpacking Boots: Specifically built for carrying heavier loads over longer distances, these boots offer robust support and cushioning.
- Trail Runners: Although not traditional boots, trail runners provide a lightweight and breathable option suitable for fast hiking and lighter loads.
- Mountaineering Boots: Ideal for rugged terrains and extreme conditions, these boots provide excellent insulation and stability but are heavier and stiffer.
Day Hiking Boots: These are typically low-cut and made from lighter materials, making them perfect for day hikes or short backpacking trips. They often feature a flexible sole for comfort but may lack the rugged durability needed for challenging trails.
Backpacking Boots: Designed for serious hikers, these boots usually have a higher cut to provide ankle support and are made from more durable materials to withstand rough conditions. They are built to handle the weight of a fully loaded backpack, offering excellent traction and cushioning for long distances.
Trail Runners: This option is gaining popularity among experienced hikers due to their lightweight design and breathability. While they may not offer the same level of ankle support as traditional boots, they allow for greater agility and are suitable for those who prefer a faster pace on less technical terrain.
Mountaineering Boots: These boots are designed for extreme conditions, providing maximum support and insulation. They are often stiffer than other types, which helps with stability on challenging climbs, but their weight and rigidity can be a drawback for casual hikers.
What Essential Features Should Every Top Hiking Boot Have?
The essential features of the best hiking boot option include:
- Durability: A good hiking boot should be made from high-quality materials that can withstand rough terrain and various weather conditions. Leather and synthetic materials are common choices, as they provide a balance of strength and flexibility while resisting wear and tear.
- Waterproofing: To keep your feet dry during wet conditions, hiking boots should have waterproof features. This might include waterproof membranes like Gore-Tex, which allow moisture to escape while preventing water from entering, ensuring comfort during hikes in rain or through streams.
- Traction: The outsole of a hiking boot plays a crucial role in grip and stability on different surfaces. Look for boots with rubber outsoles that have deep lugs or specialized tread patterns to enhance traction on rocky, muddy, or uneven trails.
- Support: Adequate ankle support is vital, especially for rough terrains. High-top boots provide more support and stability to the ankle, reducing the risk of sprains, while mid-cut boots offer a balance between mobility and support.
- Cushioning: Comfort during long hikes is paramount, and proper cushioning helps absorb shock and reduce fatigue. Look for boots with padded insoles and midsoles made from materials like EVA or polyurethane to enhance comfort and provide support for extended wear.
- Fit: A proper fit is essential to prevent blisters and discomfort. Hiking boots should be snug but not too tight, allowing for some toe movement while ensuring that the heel is locked in place to avoid slipping during descents.
- Breathability: In addition to being waterproof, the best hiking boots should also offer breathability to help regulate temperature and wick away moisture. Mesh panels or breathable linings can enhance airflow, keeping your feet cool and dry during strenuous hikes.
How Crucial Is Waterproofing for Your Hiking Experience?
Waterproofing is essential for an enjoyable hiking experience as it protects your feet from moisture and keeps you comfortable on various terrains.
- Protection from Wet Conditions: Waterproof hiking boots are designed to prevent water from entering, ensuring your feet stay dry even in rain or through puddles. This is crucial for maintaining warmth and comfort, as wet feet can lead to blisters and cold-related issues.
- Durability: High-quality waterproof materials, such as Gore-Tex, enhance the longevity of hiking boots. These materials not only repel water but also resist wear and tear, making them a reliable choice for rugged outdoor activities.
- Traction and Stability: Many waterproof hiking boots feature specialized soles that provide excellent grip on slippery surfaces. This traction is important for navigating wet rocks or muddy trails, enhancing your overall stability and safety while hiking.
- Breathability: While waterproofing is key, the best hiking boot options also incorporate breathable membranes that allow moisture from sweat to escape. This balance helps to keep your feet dry from the inside out, preventing overheating and discomfort during long hikes.
- Versatility: Waterproof boots are versatile for various weather conditions, making them a smart investment for hikers who encounter unpredictable climates. Whether hiking in the rain, snow, or through streams, waterproof boots provide the necessary protection without sacrificing performance.
Why Is Ankle Support Important for Preventing Injuries?
Ankle support is crucial for preventing injuries during activities like hiking because it stabilizes the ankle joint, reducing the risk of sprains and fractures. This support allows for better weight distribution and minimizes excessive movement that can lead to injuries.
According to the American Orthopaedic Foot & Ankle Society, footwear with proper ankle support can significantly decrease the incidence of ankle injuries, particularly in sports and outdoor activities. Research indicates that boots designed with higher collars and reinforced structures provide better protection against lateral movements that can compromise ankle stability.
The underlying mechanism involves the anatomy of the ankle, which is susceptible to sprains due to its complex structure of ligaments and tendons. When hiking, uneven terrain can cause the foot to roll outward or inward, leading to excessive strain on these ligaments. A boot with adequate ankle support limits this movement, thereby preventing overstretching and potential injuries. Additionally, the psychological aspect of feeling secure in well-supported footwear can enhance a hiker’s confidence, allowing for more natural movement without the fear of injury.
What Are the Top Brands Known for Quality Hiking Boots?
The top brands known for quality hiking boots include:
- Salomon: Renowned for their innovative designs and comfort, Salomon hiking boots often feature advanced technology such as Contagrip outsoles for superior traction and Gore-Tex waterproofing. They cater to various terrains, making them a popular choice for both casual hikers and serious trekkers.
- Merrell: Merrell boots are celebrated for their durability and support, often incorporating features like Vibram outsoles and cushioned insoles. They provide excellent stability for uneven surfaces, making them ideal for long hikes and backpacking trips.
- Columbia: Columbia offers a range of hiking boots that blend functionality with style, featuring technologies like Omni-Grip for enhanced traction and waterproof materials. Their boots are designed for versatility, suitable for both day hikes and more challenging trails.
- KEEN: KEEN is known for their toe protection and eco-friendly materials, producing boots that are comfortable and rugged. Their designs often emphasize breathability and support, catering especially to those who spend extended time outdoors.
- Scarpa: Scarpa hiking boots are favored by serious mountaineers and trekkers for their high-quality craftsmanship and performance. They are designed for technical hikes, often featuring stiffer soles for better support on steep inclines and rocky terrain.
- Hoka One One: Known for their maximalist cushioning, Hoka One One boots provide exceptional comfort for long-distance hikers. Their lightweight construction and shock-absorbing soles help reduce fatigue, making them a great option for those tackling extended trails.
- Asolo: Asolo boots are designed with a focus on performance and durability, suitable for rugged terrains. They often include features like waterproof membranes and supportive midsoles, making them reliable for challenging hikes and backpacking adventures.
What Is the Best Method to Ensure Proper Fit for Hiking Boots?
The benefits of ensuring a proper fit go beyond comfort; they also contribute to improved performance. For instance, a secure heel fit prevents slipping, which can help maintain balance on steep or uneven surfaces. Moreover, proper arch support can reduce fatigue, allowing hikers to cover more ground efficiently. According to a study published in the Journal of Foot and Ankle Research, participants wearing properly fitted hiking boots reported significantly less pain and fatigue than those with ill-fitting footwear.
Best practices for ensuring a proper fit include visiting specialty outdoor retailers where staff can provide guidance, utilizing boot fitting tools such as Brannock devices, and considering custom insoles if necessary. Moreover, hiking boots should be broken in gradually to adapt to the unique shape of the foot. Regularly checking the fit after long hikes is also recommended, as feet can change size and shape over time.
What Common Mistakes Should You Avoid When Shopping for Hiking Boots?
When shopping for hiking boots, avoiding these common mistakes can significantly enhance your experience and comfort on the trails:
- Choosing the Wrong Size: Many shoppers overlook the importance of sizing, opting for a size they believe they wear instead of trying boots on. A well-fitting boot should have enough room in the toe box and provide a snug fit around the heel to prevent blisters and discomfort during long hikes.
- Ignoring the Terrain: Different types of hiking boots are designed for various terrains, and failing to consider this can lead to poor performance. For instance, lightweight boots may be suitable for well-maintained trails, while heavier, more robust boots are necessary for rugged, uneven surfaces.
- Neglecting Break-In Time: Some buyers forget that new hiking boots require a break-in period to mold to their feet. Wearing them for short periods before embarking on a hike can help prevent blisters and ensure maximum comfort during your adventures.
- Focusing Solely on Price: While budget is important, prioritizing the cheapest option can lead to poor quality and discomfort. Investing in a high-quality pair of boots that provides the right support and durability can save you money in the long run by preventing injuries and the need for replacements.
- Overlooking Waterproof Features: Many hikers fail to consider weather conditions when selecting boots, which can result in wet and uncomfortable feet. Choosing boots with waterproof features is crucial if you plan to hike in rainy or wet environments to keep your feet dry and warm.
- Forgetting About Insulation: Insulation is often overlooked, especially in warmer climates, but it is vital for hiking in cold conditions. Boots with adequate insulation can help maintain warmth during chilly hikes, while those without can leave your feet cold and uncomfortable.
- Neglecting Comfort and Support: Some shoppers focus too much on style and appearance, ignoring the importance of comfort and support. A good hiking boot should provide ample arch support and cushioning, which can greatly affect your hiking experience and prevent foot fatigue.