Many of us enjoy exercising in some form or another.  My wife and I love to hike.  Several of my friends are CrossFit addicts.  Other friends enjoy time lifting weights in the gym or running, and others still enjoy pick-up games of some sport.  Whatever your activity is, and whatever your reason for it (health, fun, social interaction, etc.), here are some ways to get the most out of your time (scientific references listed at bottom for those further interested).

1.  Work out late in the afternoon.

A college professor once told me that the best time to exercise is “Whenever you’ll actually do it.”  I don’t disagree with this at all.  Regular and consistent exercise is better than well-timed but sporadic exercise.  Once you make the habit of exercising regularly, try doing it late in the afternoon.  While scientists are fairly vague on the exact time, you can generalize the time frame to be from 5pm-9pm, depending on when you start and finish your day.  Most athletes will say that this is when they’re at their peak physical performance, which goes hand-in-hand with when the average person’s body is at its highest activity level.  Aside from biology, the majority of athletic world records are made during this “late afternoon” time frame.

2. Exercise in bright light.

This one gets a little more technical.  Behind each eye there’s a cluster of cells called the suprachaismatic nuclei (SCN) that are responsible for the body’s biological clock — what causes you to wake up, become sleepy and hungry at regular times.  Your eye’s retinas have cells specifically for the recognition of light intensity that have a direct line with the SCN.  In effect, the brighter the light, the stronger the transmission into the SCN, which, simply, creates increased energy in the body.  Ergo, you’re able to work your body more without feeling it in the moment.

3. Exercise 2-4 hours before going to bed.

This creates longer periods of slow-wave sleep.  In short, this is the type of sleep that psychologists have deemed the most “physiologically restorative sleep” (i.e. you feel better).

4. DON’T exercise WITHIN 2.5 hours of going to bed.

While exercising 2-4 hours before sleeping creates better sleep, exercising too close to bed causes the body’s heart rate to be increased during the first few hours of sleep.  You won’t necessarily feel this the night of, but the long-term wear and tear on the body leads to high increases in cardiovascular disease.

5.  Exercise regularly, even if it’s for shorter periods.

Exercise has a dose-response pattern.  This means that the more frequently you exercise, the more positive effects it has on your body.  For example, people who work out 2 times or less per week, have significantly fewer gains (other than fat) when compared to those who work out 3 or more times per week.  Again, working out regularly (e.g. 20 minutes a day everyday) is better than working out sporadically (e.g. 1.5 hours every 4 days).

6. Avoid exercising right when you wake up.

We already know that working out in the late afternoon is best for physical performance.  When you exercise right as you get out of bed, you’re training your heart rate to spike upon awakening.  Your body naturally does this to prepare you for the day, but this causes increased wear and tear on the cardiovascular system.  As you exercise more frequently, this spike levels out.  But if you jump on the bike five minutes after waking up, you’re training your body to keep that spike in the mornings.  Assuming you don’t exercise seven days a week, 365 days a year, doing so upon awakening causes distress to your cardiovascular system on your days off.

—–

Kenneth D. Burke

References

American Academy of Sleep Medicine (2001). International Classification of Sleep Disorders, Revised: Diagnostic and Coding Manual. American Academy of Sleep Medicine, Chicago.

Barger L. K., Wright K. P. Jr., Huges R. J., Czeisler C. A. (2004). Daily exercise facilitates phase delays of circadian melatonin rhythm in very dim light. American Journal of Physiology, 288: R1077-R1084.

Beersema D. G., Hiddinga A. E. (1998). No impact of physical activity on the period of the circadian pacemaker in humans. Chronobiology International, 15: 49-57.

Cain S. W., Rimmer D. W., Duffy J. F., Czeisler C. A., (2007). Exercise distributed across day and night does not alter circadian period in humans. Journal of Biological Rhythms, 26(6): 534-541.

Cajochen C. (2007). Alerting effects of light. Sleep Medicine Reviews, 11: 453-464.

Driver H. S., Taylor S. R. (2000). Exercise and sleep. Sleep Medicine Reviews, 4: 387-402.

Kantermann T., Forstner S., Halle M., Schlangen L., Roenneberg T., Schmidt-Trucksäss A. (2012). The stimulating effect of bright light on physical performance depends on internal time. PLos ONE, 7(7): e40655.

Mistlberger R. E., Skene D. J. (2005). Nonphotic Entrainment in Humans? Journal of Biological Rhythms, 20(4): 339-352.

Myllymäki T., Kyröläinen H., Savolainen K., Hokka L., Jakonen R., Juuti T., Martinmäki K., Kaartinen J., Kinnunen M. L., Rusko H. (2011). Effects of vigorous late-night exercise on sleep quality and cardiac autonomic activity. Journal of Sleep Research, 20: 146-153.

Reilly T., Waterhouse J. (2009). Sports performance: is there evidence that the body clock plays a role? European Journal of Applied Psychology, 106: 321-332.

Schulz P., Steimer T. (2009). Neurobiology of circadian systems. CNS Drugs, 23(2): 3-13

Shiotani H., Umegaki Y., Tanaka M., Kimura M., Ando H. (2009). Effects of aerobic exercise on the circadian rhythm of heart rate and blood pressure. Chronobiology International, 26(8): 1636-1646.

Vitaterna M. H., Takahashi J. S., Turek F. W. (2001). Overview of circadian rhythms. Alcohol Research and Health, 25(2): 85-93.

Yamanaka Y., Honma K., Hashimoto S., Takasu N., Miyazaki T., Honma S. (2006). Effects of physical exercise on human circadian rhythms. Sleep and Biological Rhythms, 4: 199-206.

Youngstedt S. D., Kline C. E. (2006). Epidemiology of exercise and sleep. Sleep and Biological Rhythms, 4: 215-221.