Whether you jog in the morning or at night, you still get your aerobic exercise in for the day. Either time is a healthy time to exercise, but there are pros and cons to each that may make one preferable over the other for some. Your biological clock plays a role in what time your workout will be most effective -- usually in the evening. Otherwise, it's up to you to decide whether jogging in the a.m. or p.m. is better for you based on your own schedule-related, physical or psychological factors.
Reasons to Jog in the Morning
If you're jogging outside, it could be safer in the morning than at night, because it's easier to see cars and bicycles on the roads. Some people prefer to run on an empty stomach, though there's no scientific evidence that this improves the effectiveness of your workout. If you're training for a running event, which usually takes place in the mornings, you may want to train in the mornings. Because your body adapts to an exercise routine based on your circadian rhythms, jogging in the morning will prepare your body for running your best during a morning event. In their book "Wellbeing: The Five Essential Elements," authors Tom Rath and Jim Harter discuss studies showing that exercise lifts your mood and boosts energy for hours after your workout. If you find yourself fatigued or feeling sluggish during work, you may benefit from a morning jog for both physical and psychological reasons.
Reasons to Jog at Night
Jogging in the morning gives you an energy boost for the rest of the day, but if you want to work out during your body's physical peak, exercise later in the day. Your body's temperature is lower in the morning than at night, meaning your muscles and joints are stiffer and your lungs aren't warmed up. By night time, your body's temperature is higher, your organs and muscles are more prepared for exercise, and you're likely to have more energy from eating throughout the day. That means your performance will be better and even require less effort at night. According to a study by the University of Chicago, night exercisers burn more glucose and have a higher metabolism than morning exercisers.
Your Circadian Clock
Your circadian rhythm, or your biological clock, regulates your heart rate, blood pressure, oxygen levels, body temperature, hormone secretions and metabolism throughout the day. Your circadian rhythm plays a significant role in your athletic performance. It's based on your body's routine and the sun's rising and setting.
Find Your Circadian Peak
According to the American Council on Exercise, the optimal time to work out is when your body's temperature is at its highest during the day. Your body temperature warms up throughout the day until it reaches its peak. To calculate the time of day your body temperature is at its peak, measure and log your temperature every two hours for six days in a row. Once you've found the time when your temperature is typically at its highest, go jogging within three hours before or after that time for an optimal workout.
Lindsay Haskell enjoys writing about fitness, health, culture and fashion. She is a contributor for "Let's Talk Magazine" and "The Wellesley News." Haskell is completing her B.A. in philosophy at Wellesley College. She's also a fiction writer whose work can be read online.