What’s The Best Time For Cardio?

A question that has perplexed fitness enthusiasts for years is “weights before cardio or cardio before weights?” This debate continues because there is no correct blanket answer that covers every individual and situation. In fact, the best answer for many is “neither.”

Before workout results can even begin to be realized in the mirror or in competition the body adapts at the molecular level. Specific training leads to precise processes within the cells of the nervous, cardiovascular and muscular systems to adjust to the stress placed upon them. Multiple types of exercise won’t lead to one overall process to improve fitness. Instead, many different courses of action will occur within the body’s cells, each attempting to change the cell to protect it against future stresses.

In the 2007 review article “The Molecular Bases of Training Adaptation” Vernon Coffey and John Hawley referred to this as the “interference effect.” They explained that performing concurrent training, or training for multiple adaptations, would produce compromised results due to the competing demands on a molecular level. This gives scientific evidence for performing block periodization with elite athletes that compete in individual sports to only train for specific adaptations during certain training phases.

However, this type of training does not apply to the majority of the population. Many of us do not have the same ability to prioritize training as professional or Olympic athletes nor do we need to reach the same levels of performance in a single physical ability or even have athletic based training goals. Concurrent training is appropriate, and even preferable, for most gym rats, but we can take the research to better plan our training.

After researching the 2007 review article Dr. Coffey produced some original data to further investigate the interference effect. A 2009 paper looked into the direct effects of our original age old question and had subjects perform both weight training before endurance training and endurance training before weight training. Two important findings from this study were that endurance training before weight training decreased the anabolic effect of the resistance exercise and the cardio performed after increased inflammation and protein breakdown in the working muscles.

This has a direct effect for all training goals but especially workouts for muscle building and weight loss. It suggests that to minimize the interference between endurance and resistance training, these should be separated into different training sessions separated by as much time as possible. In an ideal world, these sessions would be performed on different days. Another possibility would be to train in two separate sessions during a single day. If neither is possible and both types of training must be performed during a single session, weight training should be performed before cardio because it is the lesser of two evils between increased protein breakdown and decreased anabolic response to training.

These recommendations apply to all training goals except one: endurance athletes. A 2011 paper by Wang et al. performed a similar study as Coffey but measured different variables as a result. Their findings showed increased aerobic abilities of the working muscles when endurance training was performed first. As a result, unlike everyone else, this population should perform both types of training within one session with cardio before weights.

Exercise and movement are an important part of any lifestyle and daily performance has a wide array of mental, emotional and physical health benefits. With busy schedules and multiple priorities, finding time to workout is not always a simple task. Thus, something is always better than nothing and a combination of resistance and endurance training, in that order, will provide optimal value. However, maximum results for general fitness, fat loss, muscle gain or strength, power and speed performance are obtained by separating the two categories of training into separate sessions. The exception lies with cardiovascular performance, in which resistance training performed after endurance workouts provide the best adaptations.


Coffey, V. G. & Hawley, J. A. 2007. The molecular bases of training adaptation. Sports medicine (Auckland, N.Z.) 37 (9), 737-763.

Coffey, V. G., Pilegaard, H., Garnham, A. P., O’Brien, B. J. & Hawley, J. A. 2009. Consecutive bouts of diverse contractile activity alter acute responses in human skeletal muscle. Journal of applied physiology (Bethesda, Md.: 1985) 106 (4), 1187- 1197.

Wang, L., Mascher, H., Psilander, N., Blomstrand, E., & Sahlin, K. 2011. Resistance exercise enhances the molecular signaling of mitochondrial biogenesis induced by endurance exercise in human skeletal muscle. Journal of applied physiology (Bethesda, Md: 1985) 111 (5), 1335-1344.