Aerobic or resistance training, or both?

Aerobic or resistance training, or both?

‍

Highlights:

‍

• Exercise routine is able to prevent multiple non-communicable diseases, improve mental health, and general well-being
• The two most popular types of exercise include aerobic exercise and resistance training
• The main benefits of aerobic exercise include improved cardiac fitness and lung function
• Properly performed resistance training strengthens muscles and improves endurance
• A combination of different types of exercise was shown to be the most beneficial approach

‍

Introduction: We need to exercise, but how? 

‍

Though the benefits of regular exercise are well-studied, more than 1.4 billion adults worldwide (more than a quarter of the population) are insufficiently active. Levels of inactivity are connected with the rapid pace of modern life but also with the difficulty of building understandable and actionable exercise routines. There are almost limitless variations of physical activity - from jogging in the park to muscle-building workouts in a gym. However, it is important to understand what kind of benefits each type of exercise can bring and how to optimally combine them for health and longevity. This article will discuss the two most popular types of exercise – aerobic and resistance training – and their interplay.

‍

Image 1

‍

Types of training

‍

Physical activity is defined by WHO (World Health Organization) as any bodily movement produced by skeletal muscles that require energy expenditure. Regular physical activity (repeated at least several times a week) is linked to the successful prevention and management of multiple non-communicable diseases, such as heart disease, metabolic syndrome, obesity, diabetes, and cancer (1). Additional benefits include improved mental health, well-being, and general quality of life.

The word "aerobic" means "related to or requiring oxygen". Correspondingly, aerobic exercise (also known as endurance or cardio training) can be defined as low- or high-intensity physical activity that depends primarily on the oxygen-consuming metabolism (2). It includes activities such as walking, cycling, and jogging. Such processes include the generation of energy from carbohydrates via mitochondrial ATP production. 

On the other hand, resistance or strength training includes activities such as lifting weights (full range of motion is essential) and is primarily anaerobic (3). In resistance training, glycolysis (4) is the primary energy process in which glucose and glycogen (the main storage form of glucose in the body) are broken down in the absence of oxygen. During glycolysis, multiple metabolites are formed, including lactic acid and inorganic phosphate. Accumulation of metabolites can lead to disruption in calcium release in muscles and, consequently, to muscle fatigue (5,6). Initially, lactic acid was thought to be a main culprit in muscle soreness, but later this view was debunked and it was proven that inflammatory response and pain result rather from fiber damage after exercise (7).

‍

Aerobic exercise: benefits and recommendations

‍

Aerobic exercise can be viewed as a positive stress stimulus for production of intracellular signaling, metabolism, and production of multiple neurotransmitters and hormones. They act synchronously to encourage mitochondrial biogenesis, antioxidant defense, cellular repair and recycling, and immunity (8). Accumulated data over the last 50 years show that aerobic exercise training promotes healthy aging and even extends average life expectancy by 3–10% (9). Widely recognized benefits of aerobic exercise training include lowered risks of obesity, type 2 diabetes, atherosclerosis, and death from cardiovascular events (10). Additionally, aerobic exercise was shown to enhance lung function and musculoskeletal integrity, decrease inflammation, balance out insulin sensitivity, and improve functions of multiple organs not directly involved in physical activity (such as skin, kidneys, and brain) (11,12). 

According to WHO recommendations (13), adults aged 18–64 should do at least 150–300 minutes of moderate-intensity or 75–150 minutes of vigorous-intensity aerobic physical activity. Examples of moderate-intensity activity include brisk walking and light-effort cycling while vigorous-intensity exercise can incorporate such activities as jogging, fast cycling, or playing basketball. Adults aged 65 years and above should aim for a similar regimen with more emphasis on light or moderate activity to avoid overexercising.

‍

Image 2

‍

Resistance training benefits

‍

The main benefits of resistance exercise include improvement of muscle strength, body composition, and endurance (14). Less known benefits include enhanced flexibility and, similarly to aerobic training, improved insulin sensitivity and decreased risk of cardiovascular disease (15). Bone density, tendon and ligament strength, and improved metabolism are also among the results of strength exercise.

The ability of resistance training to increase muscle mass makes it extremely important for healthy aging. It is well-known that aging is linked to the loss of bone and muscle mass, leading to increased frailty and fall risks. Currently, resistance training is proved to be one of the most effective interventions against muscle atrophy (16). A meta-analysis of intervention studies demonstrated that, after an average 5-month resistance training course, elderly people were able to gain more than one kilogram of muscle mass and improved their leg strength (17). Additionally, the same meta-analysis hypothesized that exercised muscles might become more susceptible to nutrients, allowing for more efficient protein synthesis.

WHO recommendations (13) include muscle-strengthening activities at a moderate or greater intensity that involve all major muscle groups on two or more days a week. In the case of older adults, particular attention should be paid to proper exercise performance, and incremental weights increase. Production of lactate can cause discomfort and limit initial performance; however, regular exercise prevents a sharp increase in lactate levels during training.

‍

Image 3

‍

Is combining even better?

‍

Both aerobic and resistance training possess proven health benefits, but the question of choice and combination remains. To answer that, we must first specify that there is no "ideal" aerobic or strength training. Each activity includes elements of another, i.e., running impacts not only aerobic capacity but also muscle strength. Moreover, many effects can overlap, such as a decreased risk of cardiovascular diseases.

However, as studies show, the unique benefits of every type of exercise result in the larger effectiveness of a combined approach. In a randomized controlled trial (18), which included obese adults aged 65 or older, it was shown that a combination of aerobic and resistance exercise improved physical function and reduced frailty more significantly than either of the approaches. A meta-analysis of training impact on patients with coronary artery disease demonstrated that combined training was more effective in improving cardiovascular fitness than any standalone training (19). In some studies, however, the improvements in cardiorespiratory fitness were highly similar (20) between single-mode and combined training. However, the reason behind this might have been the discrepancy in the protocols or the rarity of training (only once a week).

Combined training can be performed in several modes (21):

‍

• Simultaneously during the same workout;
• In one day using a split workout approach (i.e., resistance exercise in the evening, aerobic exercise in the morning);
• Separately on different days;
• In separate longer training cycles.

‍

Each exercise sequence has its advantages and disadvantages (i.e., aerobic training first can compromise the performance of resistance exercise) that should be considered when planning a training program. For older individuals, any of the protocols can be made less frequent or intense and then gradually increased according to personal limitations.

‍

Tips for professionals

‍

• Introduce your clients to the importance and health benefits of regular exercise. Share with them the existing physical activity guidelines to help formulate their goal.
• Emphasize the importance of combining both resistance and aerobic training in the exercise routine.
• A program must first deal with the challenge of the availability of time to complete the exercise sessions. Either the total time devoted on a particular day must be increased up to twofold to accommodate the two forms of exercise, or the number of exercise sessions per week must be increased. 
• It must be remembered that aerobic exercise contributes little to strength gains, and the standard strength workout only weakly increases aerobic performance.
• In concurrent training for healthy individuals, it is recommended that moderate intensities are used for both modes of exercise regardless of exercise sequence.
• Exercise sequence, frequency, and order should be chosen based on clients' preferences and specific advantages.
• If they have been leading a long-term sedentary lifestyle, your clients might need help with habit formation and adherence. 
• Estimate and analyze medical risks and problems your client already has. Overexercising might be harmful in the case of both aerobic and resistance training.
• Dietary interventions are a mandatory part of introducing a healthy exercise routine. Explain to your client that they have to follow a healthy diet to get all benefits of exercise.
• Show your clients complimentary tools, like remote apps that can be used for training while traveling or on holidays.

‍

Conclusions: Combine different exercises wisely

‍

In the modern world, physical inactivity has become one of the leading risk factors for mortality from non-communicable diseases. An efficient exercise routine is one of the main tools to address this problem and help your clients increase their life- and healthspan. Including different types of training allows to maximize the benefits and harmoniously improve an individual's state.

‍

References

‍

1. WHO: Physical activity [Internet]. 2022 [cited 2022 Jun 6]. Available from: https://www.who.int/news-room/fact-sheets/detail/physical-activity

2. Hale T. History of developments in sport and exercise physiology: A. V. Hill, maximal oxygen uptake, and oxygen debt. J Sports Sci. 2008 Feb 15;26(4):365–400. 

3. Kraemer WJ. Strength training basics: designing workouts to meet patients' goals. Phys Sportsmed. 2003 Aug;31(8):39–45. 

4. Knuttgen HG. Basic Exercise Physiology. In: Maughan RJ, editor. Nutrition in Sport [Internet]. Oxford, UK: Blackwell Science Ltd; 2000 [cited 2022 Jul 9]. p. 3–16. Available from: https://onlinelibrary.wiley.com/doi/10.1002/9780470693766.ch1

5. Westerblad H, Allen DG, Lännergren J. Muscle Fatigue: Lactic Acid or Inorganic Phosphate the Major Cause? Physiology [Internet]. 2002 Feb;17(1):17–21. 

6. Wan J, Qin Z, Wang P, Sun Y, Liu X. Muscle fatigue: general understanding and treatment. Experimental & Molecular Medicine [Internet]. 2017 Oct 6;49(10):e384. 

7. Proske U. Muscle tenderness from exercise: mechanisms? The Journal of Physiology [Internet]. 2005 Apr 1;564(Pt 1):1. 

8. Nilsson MI, Bourgeois JM, Nederveen JP, Leite MR, Hettinga BP, Bujak AL, et al. Correction: Lifelong aerobic exercise protects against inflammaging and cancer. PLOS ONE. 2020 May 13;15(5):e0233401. 

9. Reimers CD, Knapp G, Reimers AK. Does Physical Activity Increase Life Expectancy? A Review of the Literature. J Aging Res. 2012;2012:1–9. 

10. Kodama S, Saito K, Tanaka S, Maki M, Yachi Y, Asumi M, et al. Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women: a meta-analysis. JAMA. 2009 May 20;301(19):2024–35. 

11. Konopka AR, Harber MP. Skeletal Muscle Hypertrophy After Aerobic Exercise Training. Exerc Sport Sci Rev. 2014 Apr;42(2):53–61. 

12. Rauramaa R, Halonen P, Väisänen SB, Lakka TA, Schmidt-Trucksäss A, Berg A, et al. Effects of Aerobic Physical Exercise on Inflammation and Atherosclerosis in Men: The DNASCO Study: A Six-Year Randomized, Controlled Trial. Ann Intern Med. 2004 Jun 15;140(12):1007. 

13. Bull FC, Al-Ansari SS, Biddle S, Borodulin K, Buman MP, Cardon G, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med. 2020 Dec;54(24):1451–62. 

14. Poehlman ET, Gardner AW, Ades PA, Katzman-Rooks SM, Montgomery SM, Atlas OK, et al. Resting energy metabolism and cardiovascular disease risk in resistance-trained and aerobically trained males. Metabolism. 1992 Dec;41(12):1351–60. 

15. Sanavi S, Afshar R, Shegarfy L, Shavandi N. Effects of aerobic exercise and resistance training on lipid profiles and inflammation status in patients on maintenance hemodialysis. Indian J Nephrol. 2010;20(4):185. 

16. Bemben DA, Palmer IJ, Bemben MG, Knehans AW. Effects of combined whole-body vibration and resistance training on muscular strength and bone metabolism in postmenopausal women. Bone. 2010 Sep;47(3):650–6. 

17. Peterson MD, Sen A, Gordon PM. Influence of Resistance Exercise on Lean Body Mass in Aging Adults: A Meta-Analysis. Med Sci Sports Exerc. 2011 Feb;43(2):249–58. 

18. Villareal DT, Aguirre L, Gurney AB, Waters DL, Sinacore DR, Colombo E, et al. Aerobic or Resistance Exercise, or Both, in Dieting Obese Older Adults. N Engl J Med. 2017 May 18;376(20):1943–55. 

19. Marzolini S, Oh PI, Brooks D. Effect of combined aerobic and resistance training versus aerobic training alone in individuals with coronary artery disease: a meta-analysis. Eur J Prev Cardiol. 2012 Feb;19(1):81–94. 

20. Izquierdo M, Iba??Ez J, H??Kkinen K, Kraemer WJ, Larri??N JL, Gorostiaga EM. Once Weekly Combined Resistance and Cardiovascular Training in Healthy Older Men: Med Sci Sports Exerc. 2004 Mar;36(3):435–43. 

21. Kang J, Ratamess N. Which Comes First? Resistance Before Aerobic Exercise or Vice Versa? ACSMS Health Fit J. 2014 Jan;18(1):9–14. 

‍