When Is The Best Time of
Day to Exercise?
Provided
by American
Council on Exercise
What
is the best time of day to exercise? Simply put, it’s whatever time you can
commit to and be consistent. That being said, your daily rhythm and choices
affect your motivation to exercise, your recovery from exercise and,
potentially, the results you get from exercise, so there is no single “best”
time to exercise that works for everyone.
Breathing and heart rate operate optimally on a
rhythm; likewise, every system and hormone of the human body seems to function
best on a cycle. That means that the closer you get to homeostasis, the better
you can feel and the healthier you can be.
Circadian rhythm is a 24-hour body clock that
signals a multitude of physiological processes, including eating and sleeping.
Circadian rhythm is generally set by light and dark, but can be affected by
sleep habits, meal times and stress levels. Food and rest are important
foundations for exercise. Operating in sync with circadian rhythm can help
sustain adequate energy levels and ensure recovery from exercise.
“The human body likes balance and
predictability,” explains Erin Nitschke, an ACE Certified Health Coach and
Fitness Nutrition Specialist in Sheridan, Wyo. “When its natural processes are
disrupted, the body has to reorganize and compensate for whatever deficiencies
have developed as a result of an unexpected or inconsistent stimulus.”
Because of artificial light, easy access to
food and high levels of stress, we can override natural circadian rhythm quite
easily. Here are a handful of hormones and processes to keep in mind when
attempting to identify your ideal time of day to exercise.
Cortisol: The “All Natural”
Caffeine
Cortisol is called the stress hormone, but is
only problematic when it’s too high or low at the wrong time. In an ideal
circadian rhythm, cortisol rises in the morning and remains level throughout
the day to support alertness and energy.
Because cortisol is like caffeine and is
ideally rising in the morning, you may not need both. In fact, caffeine could
suppress cortisol, making it tough to feel awake without caffeine. Consider
performing your workout in the morning before you consume caffeine. Even if you
still need or want caffeine later, you’ve given your body a natural chance at
producing its own state of wakefulness.
“The research is all over the map on the best
time to exercise, mainly because research is looking at all different types of
benefits from stress management to weight loss and body composition,” says
Bronwyn Bacon, N.D. of Elevate Health in Bozeman, Mont. “For example, with
weight loss I have seen evidence that supports morning exercise being best,
whereas I’ve seen research that suggests afternoon workouts are best for
building muscle mass. For this reason, I think it’s hard to pin down a specific
time that is ‘best.’ In the end, we are far too sedentary of a society and we
are overworked, so I think it’s good to get exercise in when you can based on
your schedule.”
Adenosine Makes Muscles and
Motivation Wimpy
When you are awake, the sleep hormone adenosine
gradually inhibits the neurons in the brain and facilitates tiredness by the
end of the day. In a normal circadian rhythm, adenosine is lowest in the
morning and increases as the day goes on, while cortisol levels decline.
When you sleep, adenosine breaks down. When you
drink caffeine, you feel less sleepy because caffeine inhibits adenosine
binding by occupying the same receptors in the brain. Too much caffeine can
disrupt sleep and recovery from exercise. Not getting enough sleep at night
alters circadian rhythm. Suppressing adenosine with caffeine to counteract lack
of sleep seems to work well in the short term, but chronic sleep deprivation
has long-term health consequences.
In the afternoon, adenosine is high and
cortisol is dropping. Some people feel less energetic for this reason and might
benefit from gentle exercise, meditation or a nap. Other individuals might find
a moderate or vigorous workout helps them finish the day strong. If you feel
completely wiped out in the afternoon, you should consult with your doctor
because it could be a sign of underlying health issues.
“Some people have an afternoon slump due to
recent high stress or depression,” says Dr. Bacon. For these people, exercise
could be excellent to boost energy. In contrast, someone who is having
chronically low cortisol from long-term stress would do better with rest and
meditation. An ‘afternoon slump’ could suggest an abnormal dip in cortisol, but
it can also be due to many other things, such as high stress levels or poor
eating choices.”
The Melatonin and Core Body Temperature
Balance
Melatonin, the sleep hormone, is strongest when
you are on a regular sleep rhythm and experience consistent exposure to light.
Aim to wake up within 15-20 minutes of the same time every morning, even on
weekends. In an apparently healthy individual, this habit helps maintain a
regular rhythm for cortisol, adenosine and melatonin.
Conversely, you can give yourself a chronic
feeling of jet lag with irregular sleep habits. Without energy and motivation,
exercise is less likely to happen no matter what time of day you choose to work
out.
In addition, melatonin and core body
temperature (CBT) have an inverse relationship. As melatonin elevates with
darkness, CBT decreases; as CBT rises in the morning and lightness increases,
melatonin decreases. Exercise causes CBT to elevate and then drop several hours
later, which is why you shouldn’t exercise too close to bedtime. High CBT could
suppress melatonin and inhibit sleep. The amount of time to exercise before
bedtime varies between individuals, but three to six hours is appropriate for
most people.
“Some research studies show that morning
exercise influences higher levels of melatonin at night,” explains Dr. Bacon,
“especially if you exercise outside in the daylight.”
Your Ideal Exercise Time
It seems that morning is an idyllic time of day
to exercise, but the best way to find out is to set a strong foundation for
exercise and then experiment to find what works for you. Exercise at the same
time each day for at least a week and record how you feel (mentally and
physically) and how well you sleep. Exercise should feel good, elevate energy
and be enjoyable if you are working out and the appropriate intensity and
choosing a modality that suits you.
AUTHOR
Beverly
Hosford
Beverly Hosford, MA teaches anatomy and body
awareness using a unique method that involves a skeleton named Andy, balloons,
play-doh, ribbons, guided visualizations, and corrective exercises. She is
an instructor, author, the NFPT blog editor, and a business coach for fitness
professionals. Learn more about how to align your body and your business
at www.BeverlyHosford.com