Did you know that men who sleep less than 5 hours a night have smaller testicles than men who sleep > 7 hours a night? Or that they have a testosterone level of someone 10 years older? (1)
Women who sleep less than 5 hours a night experience a similar effect on their reproductive health.
Do I have your attention yet?
Matt Walker is a leading sleep scientist and researcher. His book “Why We Sleep” has been an incredible source of information for me as well as any of his many TED talks.
Sleep is not for babies, it is not for lazy people, it is not for the weak and it is not a luxury.
Sleep is a non-negotiable biological life support system. If you don’t sleep, you will literally die earlier. Shorter sleep = shorter lifespan.
Some people say, “well I have to get up early so I can exercise” and “I need to be healthy and get my cardio, so I don’t have a heart attack.” However, research shows a direct causation between lack of sleep and cardiovascular health. If you look at the data for cardiovascular events, such as a heart attack, there is a 24% increase risk the day after losing an hour of sleep during daylight’s savings time in the spring. And that is simply from 1 hour! You know what happens in the fall when we get an extra hour? Yep, you guessed it, there is a 24% decrease in cardiovascular events. (2) So, one of the best things you can be doing for your heart is getting at least 7 hours of sleep each night. Of course, there are other important factors that contribute to heart health, but sleep is going to be one of the most important foundations to a healthy cardiovascular system and should not be overlooked or skimped.
With COVID-19 you can’t get far without thinking and talking about the immune system. Luckily for us our immune system is stronger and more active when we are sleeping > 7 hours a night. An important part of our immune system is a cell called the natural killer cells (NKCs). Think of these guys as the silent assassins of your immune system. They identify and remove threats before you even know what hit you. Cancer cells that turn into breast, prostate and bowel cancers are more abundant in people with less sleep. NKCs are responsible for identifying these cancer cells and gobbling them up so they cannot spread, yet one study that found that sleeping 4-5 hours/night reduced the amount of NKC activities by 70%. (3).
The WHO, world health organization, has actually identified night shift work and lack of sleep as being a carcinogen since the connection between lack of sleep and cancer is so high.
Reduced sleep also changes your genetic code. One study, that can be found HERE, identified 711 out of 750 genes that are distorted with sleeping 6 hours/night for 1 week. ½ of the genes had increased activity and the other half had a decrease in activity. Unfortunately, the decrease was in the genes that assist our immune system and those that had increased activity were the genes responsible for inflammation, tumor production, stress and cardiovascular disease. Not the activity shifts we want to be seeing.
Every human being needs 7-9 hours of sleep a night. This is even more important in the endurance athlete. Getting adequate sleep is essential for long-term recovery. Many repair processes occur while you are sleeping. Neglect your sleep and your performance is definitely impaired.
Quality of sleep can vary night to night without having any significant long-term effects. Your body can cope with the occasional lack of sleep, but if you get too little sleep, stress accumulates, and you won’t recover for your next workout. If you don’t get more than 7 hours sleep in a certain night, you will want to adjust your training for that day by decreasing the intensity and duration of a workout.
Your mental clarity, reaction time, mood, and performance will all begin to suffer as well from lack of sleep.
Short naps can help with mental outlook and energy levels, but they are not a supplement to night of low sleep and do not allow you to go into the full rhythms that you get to at night.
If you need some advise on how to implement better sleep strategies please download the 8 Tips for Sleep Hygiene EBOOK