The Best Time to Run to Lose Weight

Losing weight can be achieved in many ways, as long as it results in a caloric deficit. To attain this deficit you must burn a greater amount of calories than the number of calories consumed. Keep in mind, it takes 3,500 calories to be burned to lose 1 lb. of weight. A moderate calorie diet with plenty of exercise is essential to your success.


Choosing the right time of the day to run can be influential in the effectiveness of your workouts. According to Edward Howley, professor at the University of Tennessee, states that a decrease in blood temperature results in a stronger bond between oxygen and hemoglobin, which hinders oxygen being transported to the working muscles. He further states that an increase or decrease in temperature away from the optimal temperature range causes a reduction in enzyme activity.

Fat Oxidation

One g of fat can provide 9 calories of energy, which is more than twice the energy content of carbohydrates and protein. According to the National Strength and Conditioning Association for the body to use stored fat for energy, enzymes are needed to break down the fat into free fatty acids, which can be used to fuel muscle. Exercising during the cooler part of the day is ideal to avoid enzymatic degradation.

Morning or Evening

Running in the early morning vs. the evening has physiological differences. Although both climates are cool and ideal for running, the fat-burning potential differs. Because the body is fasting overnight, without food to replenish its stored energy source, glycogen; running in the morning will force the body to use its stored fat for energy, sparing glycogen. A evening run will burn fat as well, but it takes longer to tap into that fuel source.


The American Council on Exercise states that body temperature reaches its lowest point in the morning and peaks in the late afternoon. It can be difficult for some to exercise when the body is not warmed up. Drink a protein shake at least 30 minutes before your run. This gives the body enough time to digest and provides energy for the muscles to get started while maximizing potential weight loss or fat burning.


The NSCA has stated that the body begins to adapt to high heat environments after a few weeks of training. If your schedule only permits you to run during the daytime, your body will make the necessary adjustments over time. Choosing a idyllic time to run is only one part of weight loss, the other part is time. With training, the body becomes more efficient after each run, getting you into a aerobic fat oxidation state sooner.