One of the most common questions I’ve receive in the gym has been, “What should I do first, cardio or weight training?” When I was getting my feet wet as a fitness rookie, my automatic response was, “Well… whichever one is most important to you to reach your goals. Do that one first.” Unknowingly, I may have sent many people running off (sometimes literally) on a path that may have made reaching their goals that much more difficult. The question of whether to do cardiovascular training or resistance training first in a workout has been a challenging question for many clients, gym members, and fitness professionals for some time. Luckily, there is plenty of current empirical evidence to now make a sound and educated decision.
Engaging in both cardiovascular and weight training exercises in the same session is a commonly utilized tool within the fitness community. When stacked together in the same session, the term used to describe this type of training is called concurrent training. There are specific, physiological phenomena that occur when you combine these two modalities in one session, and these phenomena vary depending upon which activity precedes the other.
Current research indicates that if both cardiovascular exercise and resistance training are performed in the same session, there is greater benefit if cardiovascular exercise precedes resistance training exercises. The primary reason for this ordering is due to caloric “afterburn” seen from each particular exercise. This afterburn, known as EPOC (Excess Postexercise Oxygen Consumption), is raised significantly following both cardiovascular exercise and resistance training. However, EPOC is significantly higher following resistance-only sessions and cardio-resistance training sessions. After 10 minutes of exercise, EPOC levels nearly double that of resistance-cardio or cardio-only sessions. After 20 minutes, EPOC levels were 60% higher for the same sessions (Drummond 2005).
While performing cardio and resistance training in the same session appears to be a time effective and traditional approach to a workout, there are some negative results from performing both in the same session. Research has determined several reasons to avoid concurrent training, and I have narrowed it down to five easy to follow rationales.
When performing cardiovascular or resistance training in the same session, exhaustion will compromise potential gains in the second activity. Strength training can produce more muscle fatigue if performed first, thus reducing the effectiveness of the cardiovascular session. Over time, this will lead to either no training gains or very minimal positive results compared with no first bout of activity (Chtara 2005).
Overtraining refers to that point at which an individual experiences physiological maladaptations and chronic performance decrements (Wilmore 2008). Some research suggests that individuals that utilize concurrent training are more susceptible to overtraining than those who do cardiovascular or resistance training alone (Bell 1991).
3. Hormone Balance
Depending on the type of exercise one undergoes, there will be a specific hormonal response in order to help the body adapt to that exact demand on the body. However, concurrent training acts like a stalemate, altering the bodies anabolic-catabolic hormone balance (growth vs. consumption). Strength training supports growth via anabolic hormones and cardiovascular exercise supports decreasing body mass via catabolic hormones. When the body functions in a catabolic state, strength development is hindered. It is noticed that cortisol (a catabolic hormone) levels increase significantly with cardiovascular exercise, while there is little or no change in anabolic hormones (testosterone and growth hormone). This leaves an individual more susceptible to overtraining (Bell 1991).
4 Skeletal Muscle Adaptations
As there is a struggle between hormone balance in the body with concurrent training, there is a struggle within skeletal muscle adaptations following concurrent training. Both cardiovascular exercise and resistance training attempt to train the body to both training extremes, with can be difficult or impossible. The premise to this lies in that the body can not adapt to two different demands from two different energy pathways (aerobic vs anaerobic) during the same training session (Chtara 2005).
5. Neuromuscular Adaptations
Human muscle tissue is comprised of two different categories of fibers, fast twitch and slow twitch. Cardiovascular activity utilizes slow twitch fibers, as they are more fatigue resistant and utilize oxygen. Resistance training activity recruits fast twitch fibers, as they fire more quickly and produce more force, but they fatigue more quickly. Training both fibers may sound ideal, but both fibers can not be optimally trained if worked in the same session. Research indicates that enhancing slow twitch fibers negatively impacts the function and recruitment of fast twitch fibers, thereby decreasing overall strength and power output (Dudley & Fleck 1987). Basically, concurrent training impairs the nervous system’s ability to fire musculature efficiently.
So by now I’m sure you are wondering, “So should I just do cardio and weights separate?” Yes and No. Concurrent training can still yield positive results, and if implemented into a program properly, these negative results will not be as apparent. It is suggested that concurrent training sessions do not exceed 3 times per week (Bell 1991). Always remember your goal. If you are an endurance athlete, the bulk of your program should be dedicated to cardiovascular activity, with strength training either following sessions or on separate training days. For those who want to see strength gains, train around an intensity of 70% of your max heart rate, as this is shown to increase cardiovascular efficiency, but does not negatively impact strength development (McCarthy 1995).
I hope this helped answer questions regarding the exercise order of your program. If you still have no idea which to perform first, leave a comment below and we can discuss what may be best for your goals.