Tom Brady goes to bed at 8:30pm every night. When asked about it during a recent radio interview, he said simply, “All of the decisions that I make always center around performance enhancement.”

What does Tom Brady know about sleep that the rest of us do not?

Maybe he’s seen one of the 750+ scientific studies that have investigated the relationship between sleep and human performance, many of which have studied elite athletes specifically. The results are compelling: Sleep improves speed, explosiveness and accuracy. It enhances our ability to process information and solve problems. It improves our judgment, composure and ability to assess and respond to situations. It accelerates physical recovery from common inflammation, stimulates muscle repair, and helps restock cellular energy in the form of glucose and glycogen.

In other words, sleep is one of the most sophisticated, potent, and powerful—not to mention legal—performance enhancers that has competition-winning potential. 

It is also one of the most underutilized. Two-thirds of adults fail to obtain the recommended eight hours of sleep nightly. You’re probably not surprised by this fact, but you may be surprised by how it affects you as an athlete. Obtain anything less than eight hours of sleep a night, and especially less than six hours a night, and the following happens:

Time to physical exhaustion drops by 10-30 percent
Aerobic output is significantly reduced
Decreased limb extension force and vertical jump height
Decreases in peak and sustained muscle strength
Impairments in cardiovascular, metabolic, and respiratory capabilities
Faster rates of lactic acid buildup
Reductions in blood oxygen saturation
Reduction in the amount of air that the lungs can expire

Just like you can’t out-train a bad diet, you can’t out-train poor sleep. In fact, research suggests that the physical and mental impairments caused by one night of bad sleep dwarf those caused by an equivalent absence of food or exercise. Put another way: Unless you’re getting at least eight hours of sleep every night, you’re undermining all your hard work in the gym and on your nutrition.

We spend too much time improving our mental and physical abilities to leave anything as powerful as sleep on the table. If you’re looking to take your performance to the next level, you have to make sleep a priority. Here are some ways to make sure you’re getting eight hours a night, from sleep expert Matthew Walker, author of Why We Sleep:

  1. Stick to a sleep schedule. Humans are creatures of habit–we have an easier time sleeping if we go to bed and wake up at the same time every day. If you take only one piece of advice from this list, this should be it. Avoid training late in the evening if possible, as it revs up our Central Nervous System.
  2. Avoid caffeine after 2pm. The effects of caffeine can take up to 8 hours to wear off fully.
  3. Avoid large meals and beverages late at night. A light snack is okay, but a large meal can can blunt our natural growth hormones overnight.
  4. Relax before bed. We’re all busy, but try to schedule some winding down time, like reading or journaling, into your nightly routine. The key here is avoiding “blue light,” such as computer work, cellphones, and artificial light which trick the body into thinking it’s daytime.
  5. Cool bedroom. You sleep better if the temperature in the room is kept on the cool side.
  6. Dark bedroom. Getting rid of all noises and lights in your bedroom promotes better quality sleep.