Suppose lactate is not cleared out and reused for energy. In that case, it will continue to build up as exercise intensity increases and cause a change in blood pH that affects muscle function, and eventually, intensity must decrease.

People taking sedating antihistamines should follow the directions on the medication or the advice of a medical professional.

We then tested 23 products, considering factors like effectiveness, usability and features. These are our top picks based on our experts' guidance and personal experiences.

“Endurance limits in terms of ultra-endurance is very much a case of trying to limit the amount of damage you do to your body in that particular event,” says Burnley.

I tried these capsules before bed — now I wish I'd known about them years ago. Not only did I drift off to sleep quickly, but my mind wasn't running an internal marathon — one of the reasons I often have difficulty falling asleep. I woke up feeling more rested than usual, and my Fitbit confirmed that I slept deeper. 

However, if you work nights, you might need to nap late in the day before work to help make up your sleep debt.

Want to stop smoking or vaping or help a loved one quit? We're here for you every step of the way with tools, tips and support. The important thing is to keep trying to quit, until you quit for good.

This tea isn't just great for bedtime — I've also found myself drinking it during stressful moments when my brain won't stop racing. Its calming effects and delicious flavor make it a staple in my tea collection. 

Watch for side effects. If you feel sleepy or dizzy during the day or if you experience any other side effects that bother you, talk to your health care provider.

A person should work with a doctor to determine what is causing their insomnia before taking sleep medications every night. A doctor will be able to advise on the best and most sustainable way to treat insomnia.

Research suggests that around half of ultramarathon competitors experience significant changes in their mental state. “You might feel a bit disoriented, a bit confused,” says Meijen. “I guess the bigger picture is self-regulation, how are you able to deal with that?”

Iodine deficiency: Your thyroid needs iodine to make thyroid hormone, so a lack of the mineral in your diet can lead to hypothyroidism. It’s the most common cause of hypothyroidism in countries that don’t have iodized salt widely available. It often causes goiter (enlarged thyroid).

You have the right to website help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only.

One user shared, "One of the best aspects of this humidifier is how quietly it operates. Even on the highest setting, it produces only a gentle hum, making it ideal for use in bedrooms or nurseries."