Do You Get Enough Sleep?

Recharging the Batteries and Measuring Sleep (1:23)

Daniel Cohen, MD, MMSc, formerly of Harvard, explains how we can recharge our internal battery to avoid sleep debt. He also explains how scientists measure sleep needs.

Sufficient sleep recharges the battery in your brain. In well-rested adults, the battery charge lasts approximately 15 hours. In those hours, you should feel alert, have an upbeat mood, think clearly, make decisions easily, and perform well at work.

If you need eight hours of sleep, but get only six hours, you will charge your battery only part way. It will drain faster than a battery that is fully charged. You likely will feel sleepier sooner, and your performance may deteriorate faster than it otherwise would. Missed sleep undermines many aspects of daily functioning, from your ability to recognize and respond to signals, to your ability to make or appreciate a joke.

People with regular work hours often go to bed around the same time on work days. Many set an alarm clock, while others awaken at the same time on their own. That means they get consistent amounts of sleep. 

Railroaders with on-call schedules or fixed hours that fluctuate over the week likely go to bed and get up at different times on different days. They often get varying amounts of sleep and likely sleep less than those with regular work hours.