Best time of day to exercise?

Dear Early bird exerciser,

The best time to exercise is the time that's right for you. Morning workouts really get some people going, release endorphins, and enhance mood. If you enjoy starting your day with a workout, or find that it's the only time you can fit it into your schedule, stick with it. Others find afternoon or evening workouts productive and stress-relieving. When you wake up, your body temperature and blood sugar levels are low, so your muscles aren't as "loose" as later in the day. In a perfect world, your muscles are warmer and fueled by a few meals (hopefully) later, well after you awake.

There isn't really a "simple" answer to your second query. It will be helpful, though, to ask yourself the following questions: How hard do you work out (intensity)? How long are your sessions (duration)? What are your exercise activities? How soon after you awake do you begin exercising? Your answers will help determine what may enhance your performance.

For some people, exercising with no fuel (food) beforehand may cause lightheadedness, dizziness, and early fatigue. Research shows that eating before exercise, as opposed to exercising on an empty stomach, improves athletic performance. If you have three hours until your workout, have a normal breakfast. However, if you're going straight to a workout after waking up, here are a few suggestions:

• If your exercise session is less than an hour, just snack on any foods that are easy to digest, such as bread, crackers, or a banana.
• If your session is one hour or longer, get up a little earlier and have something small to eat — perhaps around 250 to 300 calories — such as toast and fruit or a small bowl of cereal and skim milk.
• Drinking some water before and during exercise is important for hydration.

If you eat before exercising, make sure you allow your body some time to digest and absorb the food. During digestion, our bodies send blood to the stomach to help out with this process. When you exercise, your muscles need the blood flow, so your stomach becomes a second class citizen and digestion is slowed. If too much food is in the stomach while you're exercising, you may be uncomfortable.

Also take into account the type of food you eat and the activities you do. Some people tolerate liquids more easily because they leave the stomach more quickly than solid food. Some exercisers, such as runners, for example, would prefer not to have the internal "sloshing" around that liquids may cause.

General guidelines for eating before exercising are:

• Three or four hours before exercising, a large meal is fine (500 calories or more).
• Two or three hours beforehand, a smaller meal is suitable (400 to 500 calories).
• One or two hours before, a liquid meal is appropriate (300 to 400 calories).
• With less than one hour, a small snack will do (200 to 300 calories).

In addition, people tolerate foods differently, and the composition of the food matters. Fats stay in the stomach longest, followed by protein and high fiber carbohydrate, then low fiber complex carbohydrates, and finally simple sugars, which are absorbed fastest.

Sugary foods, such as sodas and candy, are absorbed quickly by the body and produce a sugar high within an hour of a workout. Along with a quick "sugar high" comes a quick "sugar low." People who eat sugar 15 to 30 minutes before exercising may experience a "low," with lightheadedness and fatigue, during their workout. If you feel that you absolutely must have juice or some sugary snack before exercising, have it only five or ten minutes before you begin. This way, there isn't enough time for your body to secrete insulin, a hormone which lowers blood sugar, causing fatiguing symptoms. Since everyone reacts differently, try various strategies to determine what helps you the most. No matter what, drink water before, during, and after exercise. And, have breakfast afterwards, especially if you haven't had anything to eat earlier, since this will replace glycogen stores and will keep you going all morning long.