In his book “Why We Sleep,” sleep scientist Matthew Walker, PhD points out that from a purely evolutionary point of view sleep doesn’t make sense:  When you’re asleep you cannot gather food or find a mate and reproduce, you can’t nurture or protect your offspring, and you are vulnerable to attack by human enemies and predators.

In order to outweigh these disadvantages, sleep must offer overwhelming advantages, and indeed it does. Sleep is necessary for life itself—there is a rare genetic condition that presents in middle age where people develop total, treatment-resistant insomnia, which results in death within weeks. For the rest of us, adequate sleep is imperative for optimal physical and mental wellbeing.  

Today’s column is about some disproven sleep myths:

Myth 1: If you have little to no sleep one night you can make up for it by extra sleep the next night. When length or quality of sleep is insufficient, your blood pressure, heart rate, and level of harmful stress hormones all increase, and your brain and body fail to repair and rejuvenate themselves. The resultant damage cannot be undone by sleeping more the next night.

Myth 2: Driving while intoxicated is more dangerous than driving sleep-deprived. One person dies in a traffic accident related to a fatigue-related error every hour in the U.S. Going 19 hours without sleeping causes cognitive impairment equivalent to someone who is legally drunk. If you drive after getting just 4 hours of sleep, you are 11.5 times more likely to be involved in a car accident. Drowsy truckers are especially dangerous.

Myth 3: Physical performance isn’t affected significantly by sleep. Less than 8 hours of good sleep a night, and especially less than 6, results in reduction of aerobic capacity, vertical jump height, and muscle strength; plus increased propensity for injury. NBA players who get less than 8 hours of sleep have a 29 percent drop in points per minute, a 9 percent decrease in free-throw percentage, a 37 percent increase in turnovers, and a 45 percent increase in fouls committed. Adequate sleep post-performance accelerates physical recovery.

Myth 4: Older people don’t need as much sleep as younger adults. Seniors often don’t get the recommended nightly 7 or 8 (8 ideal) to 9 hours of good sleep, for reasons discussed in a recent column in this series, but adequate sleep is just as important for them as it is for younger adults.

Myth 5:  Sleep doesn’t affect your weight. Too little sleep increases output of a hormone that makes you feel hungry, while suppressing a companion hormone that signals satiety. Sleep-deprived individuals are more apt to binge on junk food. Furthermore, sleep-deprived people who diet tend to lose muscle instead of fat.

Myth 6: If you sleep poorly, caffeine the next morning is the answer. Dr. Walker notes that after sleeping poorly “neither naps or caffeine can salvage more complex functions of the brain, including learning, memory, emotional stability, complex reasoning, or decision-making.”

Myth 7: You can learn effectively by pulling an all-nighter. If you don’t sleep well after learning, you don’t consolidate what you learned. You might be able to pass the exam, but are unlikely   to remember long-term what you learned.

Myth 8: You should avoid naps. In many primitive cultures sleep is biphasic, with 7-8 hours of sleep at night and naps of 30-60 minutes in the afternoon. Among other things, naps help consolidate memories. The only caveat is that naps late in the afternoon should be avoided because they can interfere with nighttime sleep.

Myth 9: Dreams have no purpose. Dreams occur during REM sleep. According to Dr. Walker, “dreaming takes the painful sting out of difficult, even traumatic, emotional episodes you have experienced during the day, offering emotional resolution when you awake the next morning.” Furthermore, dreams can enhance creativity. The French poet St. Paul Boux had a sign on his bedroom door that said “Do Not Disturb:  Poet at Work.”

Dr. Greg Feinsinger is a retired family physician who started the non-profit Center For Prevention and Treatment of Disease Through Nutrition. For questions or to schedule a free consultation about nutrition or heart attack prevention contact him at gfeinsinger@comcast.net or 970-379-5718.