Soy Protein and Cardio
We don’t think of protein as a way to improve cardiovascular performance in the same light as we do with strength gains. If protein improves strength, does it also do the same with cardio? More specifically, does soy protein improve cardiovascular performance? Let’s take a look at the research to find out!
Research on Soy Protein and Cardiovascular Exercise
Soy Protein as a Pre-Workout1
Though protein products are typically thought of as post workout supplements, another option is using them before a workout. A 2010 study looked at whether soy protein, taken before high intensity aerobic exercise, improved performance.
Eight male cyclists participated in this study. Participants’ cycling performance was tested with two different supplements and a placebo: 1) carbohydrate-only supplement, 2) carbohydrate and soy protein supplement, 3) placebo. The supplement or placebo was given to participants three times throughout the trial: at 0 minutes, 20 minutes, and 40 minutes.
The results showed that the carbohydrate and soy protein mix increased endurance 84% compared to the placebo and 37% compared to soy protein alone. The researchers concluded that a soy-carb mix taken before a workout could improve endurance performance.
Soy Protein as a [sort of] Post-Workout2
Another, more traditional route with protein, is taking it as a post workout recovery aid. A 2016 study looked at how well soy protein worked in this setting. This study compared soy protein to chocolate milk, a hemp drink, low fat milk, and an artificially sweetened beverage.
The participants performed a high intensity interval workout designed to fatigue the body. Once the subjects completed this phase of the workout, they drank their assigned recovery drink (soy protein, chocolate milk, a hemp drink, low fat milk, or a placebo – artificially sweetened beverage). The subjects spent the next four hours resting. Following the rest period, subjects completed a 20-km cycling timed trial.
The results showed the recovery drink group performed significantly better in the 20 km timed trial than the subjects who took the placebo. There was no significant difference in performance between the various recovery drinks. The authors concluded that all of the carbohydrate and protein recovery drinks improved endurance.
The Bottom Line – What does this research mean?
The research on soy protein’s effects on cardio is limited. Even so, the small amount of research does suggest that soy protein has the potential to improve cardiovascular performance when taken before a workout. This performance increase is further aided when mixed with carbohydrates.
Whether or not soy protein improves recovery from cardio type workouts is an open question. There is however, an abundance of literature looking at how other sources of protein impact recovery from aerobic exercise. In a 2014 review, researchers concluded, “Overwhelmingly, studies have consistently demonstrated the acute benefits of protein supplementation on post-exercise muscle anabolism, which, in theory, may facilitate the recovery of muscle function and performance3.” It’s a safe assumption that soy protein provides similar benefits.
The limited amount of research suggests that soy protein, when mixed with carbohydrates, probably improves performance when taken before exercise. It’s also safe to assume, soy protein aids in cardio workout recoveries.
- Ghosh, A. K., Rahaman, A. A., & Singh, R. (2010). Combination of Sago and Soy-Protein Supplementation During Endurance Cycling Exercise and Subsequent High-Intensity Endurance Capacity. International Journal of Sport Nutrition and Exercise Metabolism, 20(3), 216–223. doi: 10.1123/ijsnem.20.3.216
- Upshaw, A. U., Wong, T. S., Bandegan, A., & Lemon, P. W. (2016). Cycling Time Trial Performance 4 Hours After Glycogen-Lowering Exercise Is Similarly Enhanced by Recovery Nondairy Chocolate Beverages Versus Chocolate Milk. International Journal of Sport Nutrition and Exercise Metabolism, 26(1), 65–70. doi: 10.1123/ijsnem.2015-0056
- Pasiakos, S. M., Lieberman, H. R., & Mclellan, T. M. (2014). Effects of Protein Supplements on Muscle Damage, Soreness and Recovery of Muscle Function and Physical Performance: A Systematic Review. Sports Medicine, 44(5), 655–670. doi: 10.1007/s40279-013-0137-7