There is little research available regarding the influence of performing aerobic exercise combined with strength training on the acute response of testosterone and cortisol. Conducting both aerobic and strength training together can generate a higher metabolic demand, resulting in increased release of cortisol, which may negatively influence the release of testosterone during the training session1.
The Downfalls of Concurrent Training
Conducting aerobic and strength training together is called concurrent training, and evidence shows that aerobic training may negatively influence the development of strength normally occurring from strength training. This is regarded as the interference effect 2,3.There is a host of factors that can hamper strength gains when conducting concurrent training such as low muscle glycogen which leads to a chronic catabolic state, antagonistic protein synthesis signaling, ultimately interfering with the magnitude of muscle hypertrophy, impairment of neural adaptations occurring from resistance training and peripheral fatigue resulting from aerobic training.
There is a host of factors that can hamper strength gains when conducting concurrent training such as low muscle glycogen which leads to a chronic catabolic state, antagonistic protein synthesis signaling, ultimately interfering with the magnitude of muscle hypertrophy, impairment of neural adaptations occurring from resistance training and peripheral fatigue resulting from aerobic training.
The large volume of training that occurs from concurrent training can lead to a steep rise in the resting levels of cortisol and an imbalance among the anabolic hormones (i.e., testosterone, growth hormone) and catabolic hormones (i.e., cortisol), consequently producing an unfavorable environment for developing muscle mass4. Some research observed an interference effect on developing strength and muscle mass that paralleled the increase in resting cortisol concentrations 4,5. The role of hormone concentrations in the interference effect is typically investigated by assessing circulating testosterone and cortisol at rest 2,4.
The influence of manipulating the order of strength and aerobic training on the pattern of acute response of testosterone and cortisol in a concurrent training session hasn’t been investigated.
It is important to determine the influence of simultaneous performance of aerobic and strength training on the acute hormonal response to strength training adaptations because many recreational and elite athletes include both modalities in their training regimens. Moreover, it is important to determine the best order of both modalities during concurrent training to optimize a more anabolic hormonal response.A collaborative study by
The Study
A collaborative study by Federal University of Rio Grande do Sul, Porto Alegre, Brazil and Public University of Navarre, Navarre, Spain investigated the order effect of aerobic and strength training on the acute response of testosterone and cortisol during a concurrent training session. The researchers hypothesized that performing aerobic exercise before resistance exercise could negatively affect the acute testosterone response6.
Ten recreationally strength-trained young men performed 2 exercise interventions: aerobic-strength (AS) and strength-aerobic (SA), which consisted of 30 minutes of aerobic exercise on a cycle (75% max HR) and 3 sets of 8 repetitions (75% of 1RM) in 4 strength exercises (bench press, squat, lat pull-down, and knee extension). Testosterone and cortisol were assessed before, between exercise modalities and immediately after the concurrent training session. Testosterone significantly increased after the first modality regardless of order. However, testosterone remained significantly higher after the second modality only in the AS order. Cortisol increased after the first modality in both orders but returned to resting levels after the second modality in both AS and SA interventions.
The Results
These results suggest that testosterone is optimized after the AS order. These finding should be applied only when short duration and moderate intensity aerobic training is performed. It appears that performing the aerobic strength modality order may maintain the acute increase in testosterone levels for a longer period compared to the inverse order. To optimize both modalities, the ideal situation is to separate them by 8 hours or more.
Given the busy schedule that trainers and their clients endure, it is evident from this study that when performing both modalities within the same session, it is best to begin with aerobic training and end with strength training to optimize the testosterone response. More research is needed over a longer term (e.g. 12 weeks) to ascertain the effect this modality order on strength and hypertrophy gains.
A Powerful Strategy
If you have to perform both aerobic and strength training within the same session; I recommend you consume a quick-acting protein/carbohydrate beverage. Combine a serving of VP2 Whey Protein Isolate and DGC (Dextrorotatory Glucose Crystals) between the aerobic and strength session will help prevent you from going into a catabolic state and muscle protein being used for energy sources during the strength training session. This nutritional intervention will prevent protein degradation, enhance protein synthesis and provide energy (glucose) that will be readily used during the resistance training!
References:
1. Brownlee K, Moore, AW, and Hackney, AC. Relationship between circulating cortisol and testosterone: Influence of physical exercise. J Sports Sci Med 2005;4:76-83.
2. Cadore EL, Pinto RS, Lhullier FL, et al. Physiological effects of concurrent training in elderly men. Int J Sports Med 2010;31:689-97.
3. Hakkinen K, Alen M, Kraemer WJ, et al. Neuromuscular adaptations during concurrent strength and endurance training versus strength training. Eur J Appl Physiol 2003;89:42-52.
4. Bell GJ, Syrotuik D, Martin TP, Burnham R, Quinney HA. Effect of concurrent strength and endurance training on skeletal muscle properties and hormone concentrations in humans. Eur J Appl Physiol 2000;81:418-27.
5. Kraemer WJ, Patton JF, Gordon SE, et al. Compatibility of high-intensity strength and endurance training on hormonal and skeletal muscle adaptations. J Appl Physiol 1995;78:976-89.
6. Cadore EL, Izquierdo M, Santos MG, et al. Hormonal responses to concurrent strength and endurance training with different exercise orders. J Strength Cond Res 2012;26:3281-8.
