Exercise as it relates to Disease/Can strength training help improve cardiovascular function?

This is a critique of the journal article "Effects of high-intensity strength training on cardiovascular function, Hurley & Seals et al (1984)"

What is the background to this research?[edit | edit source]
VO2 max is a measure of the most amount of oxygen that can be utulised during exercise and is the best measure to determine cardiovascular fitness. Having a high VO2 is associated with a reduction of cardiovascular events.

Resistance training is a popular form of exercise. It promotes many health benefits such as increasing musculature and promoting bone health. However, since it does not increase heart rate to the extent or duration that cardio work does, its effects on VO2 may be minimal, and therefore, might not aid in cardiovascular health. This implication questions the impact strength training has on cardiovascular fitness and whether endurance or aerobic type training is the only way to improve cardiovascular fitness.

The experimenters in the paper by Hurley & Seals et al performed a study to test if a strength training program was enough to elicit an impact of cardiovascular function. The findings of the article my highlight the impacts of strength training on cardiovascular functions and subsequently, may assist in determining what role strength training has in a fitness routine.

Where is the research from?[edit | edit source]
Hurley & Seals et al from the Washington school of Medicine.

What kind of research was this?[edit | edit source]
This was a quantitative research study that involved an original experimental design. Data from the study was collected and analysed by the experimenters.

What did the research involve?[edit | edit source]
13 healthy untrained males aged between 40-55 years underwent a 16 week high intensity strength training program performed on a Nautilus machine. Prior to beginning this program they performed a submaximal VO2 test to determine what their level was. After completing the 16 week strength program, the participants underwent the same submaximal VO2 test to determine if any change occurred in their oxygen uptake capacity. There was a control group of 10 men aged between 40-64.

The strength program was performed solely using a Nautilus machine, with no free weight or barbell compound exercises implemented and the heart rate of the individuals was not taken while they performed the strength training program. Increasing cardiac output is a possible mechanism by which strength training increases VO2, but participants heart rate was not monitored during the 16 week strength program and so it is difficult to conclude if they were exercising and a sufficient intensity. This raises an issue of the data for the experiment. The sample size was small and highly specific (older, male, untrained) which means their results might not reflect accurate data for everyone. The study is dated and shows differing conclusions from more recent studies such as the one by Inga et al which contained a larger sample size and found that in obese individuals, both strength and aerobic training improved oxygen uptake.

What were the basic results?[edit | edit source]
The researchers found that the participants that performed the strength program gained significant muscular strength, their one rep max increased one average by 44% for various exercises. There was no change in body weight or body fat percentage, however, researchers noted an increase in fat free weight. Notably, there was no increase in oxygen uptake for either the control group or the group that underwent the strength training program. The hemodynamic response to the submaximal VO2 test also did not change after the program was performed.

What conclusions can we take from this research?[edit | edit source]
From the experimental study, it can be concluded that a high strength program with variable resistance will not improve VO2 max, However, this does not seem to be the case. More recent papers have shown the opposite is true, particularly Ozaki et al. What is important to note is that while Ozaki et al found improvement in VO2 after a strength training program in some cases, volume, intensity or rest between sets were not the factors that seemed to have an impact on the improvement of VO2 in both older and younger subjects. This led them to the suggestion that strength training elicits increase in oxygen uptake by means of increasing heart rate. Strength training also offers other cardiovascular benefits. A paper by Liu et al conducted a research study which included over 12,000 men. It concluded even 1 hour a week of resistance training significantly reduced the chances of having a cardiovascular event, and suggests that the main health benefits from aerobic exercise is its ability to help reduce weight. From the research by Hurley et al, there is not much we can conclude without more information.

Practical advice[edit | edit source]
Individuals should incorporate a variety of exercises in their regiment to reap the benefits of the different forms of training depending on their current fitness level. VO2 will not increase without a sufficient stimulus and so, individuals with a higher fitness level should incorporate exercises styles such as HIIT or working at a relative intensity of 90-100% of aerobic capacity to efficiently stimulate change in their oxygen uptake. Both cardio and resistance training improve cardiovascular fitness and offer health benefits. Resistance training can help improve cardiovascular fitness in individuals beginning with lower fitness levels. Since both training styles can improve cardiovascular health, fitness levels, individualization and preference of exercise type are perhaps more important factors for individuals to choose what to train, particularity if there arises contraindications for training types.

Further information/resources[edit | edit source]

 * Strength training: Get stronger, leaner, healthier https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/strength-training/art-20046670
 * Cardiovascular Training Vs. Strength Training for Weight Loss https://www.beaumont.org/services/weight-loss/cardiovascular-training-vs-strength-training-for-weight-loss
 * Why Weight Lifting Is Good for Heart Health https://selecthealth.org/blog/2019/02/why-weight-lifting-is-good-for-heart-health
 * How pumping iron can reduce your heart attack risk https://www.eehealth.org/blog/2019/12/lifting-weights-for-heart-health/