Cardio Vs. Weights: Which Should You Do First?

One of the most frequently asked questions I get as a fitness professional is, "If I am going to do my cardio and strength training on the same day, which comes first?" The simple answer is that the order of operation depends on the individuals goal.

If your primary goal is to increase your aerobic endurance or lose body fat, then you should perform cardio first. If your primary goal is to increase muscular strength, then do strength training first. To get the most out of your workout, perform the exercise that is most important to your goals first, when you are not fatigued.

Finnish researchers hypothesized that by doing cardiovascular exercise prior to strength training, it might make muscles weaker and reduce the ability to lift heavy weights. According to Fabio Comana, director of Continuing Education for the National Academy of Sports Medicine, "Doing cardio first will induce fatigue that may compromise technique and possibly increase risk of injury," Exhausting oneself with a big run right before weights and resistance training doesn't just up the risk of injury, it also means you'll have less energy to throw into a really good weight training session.

The majority of fitness experts will advise you to do the cardio after the weight training, because if you do cardio first, it uses up much of the energy source for your anaerobic work (strength training) and fatigues the muscles before their most strenuous activity. 

This same view holds that strength training first will deplete the muscles' stored carbohydrates (glycogen or sugar), and therefore, will enhance fat burning during the cardio workout due to the lack of available sugar for fuel. Once glycogen is depleted, the body turns to more long-term storage sources, like fat. When it comes to analyzing the percentage weight loss that's comprised of fat versus lean tissue like muscle, weights have cardio beat overall.

It's important to get the opinion of a doctor and certified personal trainer or exercise professional before proceeding, but the takeaway is simple: if you're exercising, no matter the order, you aren't doing anything wrong. Depending on your goal, you may want to choose one type of exercise over the other. Of course, you could alternate days and avoid the question entirely.

STAY FIT. STAY CLASSY. STAY TRUE, 

Jenna

References: 

http://www.military.com/military-fitness/running/cardio-or-weights-which-comes-first

http://www.huffingtonpost.com/2012/08/06/cardio-or-weights-first-exercise-order_n_1739089.html