A late workout should not hinder your sleep

Exercise science specialist Shawn Youngstedt, who is a professor of nursing and innovation at Arizona State University, said: "Exercise in the evening does not disturb sleep and can even promote sleep a little bit."
Exercise science specialist Shawn Youngstedt, who is a professor of nursing and innovation at Arizona State University, said: "Exercise in the evening does not disturb sleep and can even promote sleep a little bit."PHOTO: REUTERS

Even if you do not have a 9-to-5 job, running outdoors on a hot day could be dangerous.

In addition to the risk of sunburn and heat rash, as well as the long- term cancer risk of sun exposure, exercising in a sunny and hot environment can cause fluid shifts in your skin as you sweat, said Associate Professor Adam Friedman, who specialises in dermatology at George Washington University.

This can stretch and damage your skin, and increase the likelihood of wrinkles and fine lines, he added.

A solution would be, perhaps, to run at night. But would exercising at night keep one awake?

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According to Ms Amanda Kim, a spokesman for Under Armour, most of the runs logged in the United States last year on one of the Under Armour apps were at 5pm in the winter and 6pm in the summer months.

Dr Charles A. Czeisler, director of the division of sleep medicine at Harvard Medical School, said: "Most people used to think it was too energising to exercise in the evening."

His medical practice includes providing sleep consultations to professional athletes and sports teams.

Dr Czeisler said he is not aware of any evidence that suggests an adverse impact from exercising in the evening. For people who are training - no matter what time of day - exercise actually helps to increase the depth, or quality, of sleep, he said.

Exercise science specialist Shawn Youngstedt, who is a professor of nursing and innovation at Arizona State University, said: "Exercise in the evening does not disturb sleep and can even promote sleep a little bit. Exercise ending even half an hour before bedtime does not disturb sleep for most people."

Dr Czeisler said that it is not so much when you exercise that affects sleep, but how consistent you are with your wake time and your sleep time, as well as what you eat and when.

The idea is to try to keep the interval between your first meal and your last meal of the day on the order of 12 hours or less, he added. It means that if you are having breakfast at 8am, you do not want to eat dinner after 8pm.

He said that eating a meal after your body begins to release the hormone melatonin - which happens after the sun sets and helps to maintain glucose levels during the night - can interfere with your circadian rhythm, which has the greatest impact on your sleep.

And that is where evening workouts can be tricky.

To train optimally, a person who eats breakfast at 8am would need to finish running (and stretching) at least by 7.30pm to finish eating at 8pm.

But there are some days when it might not be possible to do everything right. Mr Youngstedt said: "People should exercise when it is convenient, when they can consistently do it."

Dr Czeisler pointed out: "The three pillars of good health are nutrition, exercise and sleep. But they should not be at odds with each other.

"Exercising at 4am and, therefore, not sleeping, or getting up at 5am and losing two hours of sleep in order to exercise is a bad idea, just as eating in the middle of the night is a bad idea."

Long-distance running can also increase your sleep needs, which can average between seven and nine hours, depending on your age, he said.

According to Philadelphia sports dietetics specialist Kelly Jones, if you are planning to exercise in the evening, it is important to eat throughout the day to fuel your workout and to prevent overeating afterwards. But you should not be tempted to exercise and go to sleep without eating, she said.

Specific foods to avoid at night include anything with excessive sugar or caffeine, Ms Jones said.

If you are exercising for longer than an hour, even in the evening, you should consider fuelling during the workout, she said.

She warned that energy drinks contain caffeine, so one should check the label before consuming.

THE WASHINGTON POST

A version of this article appeared in the print edition of The Straits Times on June 27, 2017, with the headline 'A late workout should not hinder your sleep'. Print Edition | Subscribe