Q: What are the physiological differences between someone who gets by on 5 hours vs. 7 hours of sleep a night? I’ve heard that some people are “just fine” on only 5 hours.A: Sleep research has found significant health issues related to differences in sleep duration. Mortality studies suggest that those who get less than seven hours have a shorter life span, as well as an elevated risk of coronary artery disease, stroke and hypertension, obesity, and diabetes. On the cognitive side, those who sleep five hours or less have shorter attention spans, more negative emotions and less memory recall.
First off, the recommended sleep averages are only that: averages. Every person has a unique relationship to sleep and health, and the most important goal in learning more about your sleep patterns is to find what works for you. The goal with sleep health is finding the factors that lead to you feeling refreshed after sleep and invigorated throughout the day.
That said, research into sleep has found significant health issues related to differences in sleep duration. Mortality studies suggest that those who get less than seven hours (as well as much more than seven) have a shorter life span. The risk of disease due to consistent sleep restriction of five hours or less is also elevated, particularly coronary artery disease, stroke, and hypertension. Those who sleep less than seven hours are also more likely to be obese, diabetic and have compromised immune systems as well as high blood pressure.
Particular at risk for cardiovascular disease are adults 60 years and older who sleep five hours or less. The chance of getting this disease is up to three times greater than those who sleep seven hours, according to a 2010 study.
On the cognitive side, those who sleep five hours or less have shorter attention spans, more negative emotions and less memory recall. On top of that, longer reaction time is another cognitive trait of sleep restriction, meaning that it could take you twice as long (if not longer) to perform tasks or react in a dangerous situation. If you’re driving after not getting enough sleep, that extra second it takes for you to keep your car from drifting could mean the difference between life and death.
As if that wasn’t enough, those who sleep less than 7 hours tend to make poorer food choices. Even if you normally shun high fat, sugary foods, that double chocolate glaze on the break room table looks more tempting to a sleep deprived brain than a well-rested one. And of course, those who sleep five hours of less are often fatigued during the day, and more likely to need stimulants in the morning and for making it through the day. As a side note: true “short sleepers” often don’t require caffeine or a nap to keep them going during the day.
In short, when you’re cutting back on the sleep, your body notices it on many different levels. To keep everything in good working order—as well as staying fit, smart, and having more energy all around—make sure you’re getting an adequate amount of sleep every night.
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