What Comes First - Cardio or Weights?

I get asked a lot, "Should I do weights or cardio first?" It is not such a simple answer. The answer depends on what your fitness goals are. Your goals depend on whether you should do cardiovascular exercise before or after weight training.

Cardiovascular exercise (cardio) is aerobic activity that uses oxygen at a rate in which the respiratory system can replace oxygen to working muscles that places consistent demands on the heart, lungs and the cardiorespiratory system. Some examples include; walking, running on the treadmill, or riding a bike. Cardio exercise is done at a sustained pace over a long period of time. Blood glucose, stored glucose and fat are the main fuel source.

Weight training exercise is anaerobic activity which is activity in short bursts in which the muscles demand for oxygen is exceeded. Stored muscle glucose and phosphocreatine and the main fuel sources.

Now that your know the difference between the two exercises, let's go over some different scenarios that answer the question which exercise you should do first.

Weights before cardio. If weight training is done before cardio, you have a lot of energy to focus on weight training. Many people do not want to spend too much time doing cardio before weights because they believe that they will not have enough energy to lift well. However, doing 45 minutes of moderate level cardio is not enough to significantly deplete your energy sources.

Doing cardio after weights also may allow you to burn more fat. This happens because during wight training your body will deplete some carbohydrate stores that will put you in fat burning mode.

Cardio before weights. If cardio is done first thing, you will be able to do this more efficiently. A tired body after weight training does not yield a higher aerobic fitness outcome. If you want to lose weight and maximize aerobic fitness, it is essential that a quality cardiovascular exercise is done to maximize output.

A study from the Human Performance Research Center at Brigham Young University tested these different scenarios.
- EPOC, which is the measure of after burn, or energy output, after exercise is stopped is the greatest when cardio was done BEFORE weight training.
- Cardio AFTER weights is more difficult, which has implications for efficiency and safety.
- It is recommended that cardio be done BEFORE weights when combining them into one workout.

The answer? It is quite complex, but it is recommended that cardio be done before weights for the general population. If weight loss is not your goal and you are a body builder, cardio and weights can be done on different days. If increasing muscle mass in your goal, it is important to not skip cardio! Your body is unique, listen to it and do what you think is best.

Sources
Drummond MJ, Vehrs PR, Schaalje GB, Parcell AC. Aerobic and resistance exercise sequence affects excess postexercise oxygen consumption. J Strength Cond Res. 2005 May;19(2):332-7.

Miyachi M, Kawano H, Sugawara J, Takahashi K, Hayashi K, Yamazaki K, Tabata I, Tanaka H. Unfavorable effects of resistance training on central arterial compliance: a randomized intervention study.Circulation. 2004 Nov 2;110(18):2858-63.