| Contrary to popular belief, women aren't the only ones | | | | Don't Fix It If It's Not Broken |
| with biological clocks. We all have them, and heed their | | | | First of all, don't change your schedule if you feel good |
| ticking on a daily basis. If you are a regular exerciser, | | | | beginning your day with exercise. Everyone agrees |
| you may have already determined your most | | | | that exercise at any time is better than no exercise at |
| productive time to exercise and follow a routine that | | | | all. In fact, people who exercise in the morning are |
| works best for you. On the other hand, if your | | | | more successful at making it a habit. And though it has |
| exercise time varies from day to day, and it's wearing | | | | been suggested that morning exercise may put some |
| you out instead of pumping you up, you may be | | | | people at higher risk for heart attack, further research |
| interested in the work of scientists who are studying | | | | indicates that there is simply a generalized increased |
| the proverbial internal clock and how to best determine | | | | risk of heart attacks in the morning. If your schedule |
| what time of day you should schedule your workouts. | | | | favors an early workout, emphasize stretching and a |
| Rhythm: It's Not Just For Dancing | | | | good warm-up to insure that your body is ready for |
| The secret appears to lie in circadian rhythms, the daily | | | | action. |
| cycles that our bodies follow. These rhythms originate | | | | Other Considerations |
| in the hypothalamus and regulate everything from | | | | If stress relief is your goal, exercise always works, all |
| body temperature and metabolism to blood pressure. | | | | the time. And if you're wondering when it's best to train |
| The rhythms result from the firing rate of neurons. | | | | for an upcoming event, it all depends on what time |
| They have conformed to our 24-hour light-to-dark | | | | you'll actually be competing. If an upcoming marathon |
| cycle, and may be regulated and reregulated each day | | | | begins at 7:00 a.m., try training at that time of day. |
| according to the environment. | | | | Though training at any time of day will raise |
| Warm Is Better | | | | performance levels, research has shown that the |
| It is the influence of circadian rhythms on body | | | | ability to maintain sustained exercise is adaptive to |
| temperature that seems to yield the most control over | | | | circadian rhythms. In other words, consistently training in |
| the quality of a workout. When body temperature is at | | | | the morning will allow you to sustain exercise during a |
| its highest, your workouts will likely be more productive; | | | | morning marathon longer than if you train in the |
| when your temperature is low, chances are your | | | | evening. |
| exercise session may be less than optimal. Body | | | | Find Your Peak |
| temperature is at its lowest about one to three hours | | | | To determine your own circadian peak in body |
| before most of us wake up in the morning, in contrast | | | | temperature, record your temperature every couple of |
| to late afternoon when body temperature reaches its | | | | hours for five to six consecutive days. Body |
| peak. (To determine your own circadian peak, refer to | | | | temperature usually fluctuates by plus or minus 1.5 |
| the box to the right.) Studies have consistently shown | | | | degrees throughout the day. Try exercising during the |
| that exercise during these late-in-the-day hours | | | | period three hours before and after your highest |
| produces better performance and more power. | | | | temperature. If you are an early bird or a night owl, you |
| Muscles are warm and more flexible, perceived | | | | may notice that your temperature peaks one to two |
| exertion is low, reaction time is quicker, strength is at its | | | | hours before or after the norm (between 4 p.m. and 6 |
| peak, and resting heart rate and blood pressure are | | | | p.m.); you can adjust your exercise time accordingly. |
| low. | | | | |