We all know we feel best after a good night’s sleep. Have you noticed when you come home from a trip or finish a big day of training, there is nothing like your own bed? For years I have been preaching to my athletes to get a good bed as an essential piece of ‘training’ equipment… and use it properly! Sleep is one of the most important things that endurance athletes can do to improve on a daily basis, yet it is often the time we tend to steal from the most. 

Triathletes tend to divide their training time between swim, bike, run and even strength workouts efficiently but often sleep is left as a lower priority. 

Why is this?

The saying “I’ll sleep when I’m dead” is not a good motto…

Here’s why you need your sleep:

1: Sleep deprivation can slow glucose metabolism –  Eve Van Cauter, Ph.D., from the University of Chicago Medical School, studied the effects of three different durations of sleep in 11 men ages 18 to 27. For the first three nights of the study, the men slept eight hours per night; for the next six nights, they slept four hours per night; for the last seven nights, they slept 12 hours per night. Results showed that after four hours of sleep per night (the sleep deprivation period), they metabolized glucose least efficiently

2: Increased cortisol levels come from sleep deprivation – Levels of cortisol (a stress hormone) were also higher during sleep deprivation periods, which has been linked to memory impairment, age-related insulin resistance, and impaired recovery in athletes.

3: Sleep deprivation can cause decreased activity of human growth hormone. This is a critical for muscle tissue repair after exercise. I.e. when your muscles repair, you get stronger, and you race faster!

4: Motor skills deteriorate and reaction time increases. This is important if you don’t like crashing your bike. Hans Van Dongen, Ph.D., and David Dinges, Ph.D., of the University of Pennsylvania, described studies assessing psychomotor vigilance performance after sleep deprivation. This skill involves reaction time and sustained attention. It is needed for not only sports performance but also everyday activities such as driving. It is highly sensitive to sleep loss, often experienced by athletes on road trips, particularly after they cross multiple time zones.

Do you sleep enough?

William Dement, M.D., Ph.D., a professor of psychiatry and sleep researcher at Stanford University, states that chronic sleep restriction which is widespread amongst North American adults, has serious adverse consequences for physical and mental performance. More importantly he states that sleep loss is cumulative. He calls this “sleep debt.” He explains that the brain records as a debt every hour of sleep that is less than a person’s nightly requirement. A large sleep debt can be reduced only by extra sleep. In a landmark 1994 National Institute of Mental Health study, subjects stayed in bed in the dark 14 hours every night for 28 consecutive nights. At first, they slept as long as 12 hours a night, suggesting they entered the study with sizeable sleep debts, Dement said. By the fourth week, their sleep stabilized at a nightly average of eight hours and 15 minutes – meaning that most adults need this amount of sleep each night.

Go to bed. Get better results.

Glucose and glycogen (stored glucose) are the main sources of energy for athletes. Being able to store glucose in muscle and the liver is particularly important for endurance athletes. Those who are sleep deprived may experience slower storage of glycogen, which prevents storage of the fuel an athlete needs for endurance events beyond 90 minutes. Elevated levels of cortisol may interfere with tissue repair and growth. Over time, this could prevent an athlete from responding to heavy training and lead to overtraining and injury.

So, if you are up late reading now, then get to bed! If your bed is keeping you up at night, then get a new one!


Lance Watson, LifeSport head coach, has trained a number of Ironman, Olympic and age-group Champions over the past 30 years. He enjoys coaching athletes of all levels.