Aerobic exercise vs. strength training for women: which is better?
I’ve been teaching university courses on exercise for more than a decade, and one question my undergrad and graduate students inevitably ask is, “Which is better – cardio or resistance training?” Lately I’m hearing this question a lot from my female followers on social media, often with follow-ups around cycle syncing and optimizing fitness during the peri- and postmenopausal life stages.
When I was growing up, all the magazines at the grocery checkout said that cardio was best, but now the media is touting the benefits of resistance training versus aerobic exercise. At least in the headlines, it feels like there’s been a switch to prioritize weights over running. While it’s probably obvious that both offer unique advantages, the question persists: is one superior for a longer, healthier life?
First things first: pick exercise that you enjoy and stick to it.
The most important thing to remember when choosing an exercise regimen is not aerobic vs. resistance training. The most critical part to training, and thus longevity, is to first choose a physical activity that you enjoy (or maybe even LOVE) and that you will continue to do regularly.
If you embark on a protocol that you hate, or one that makes you feel uncomfortable or overly stressed because you feel obligated to do it, it won’t last. On the other hand, if you start with something you enjoy, and something that gets you excited to train, you’re already doing it right. From there, you can start to experiment with new modalities because your body and mind will be in sync. Remember, if you’re in it for longevity, you’ve gotta play the long game.
Let’s break down how aerobic and resistance training affect your body physiologically.
Aerobic exercise, (i.e. “cardio” like running, swimming, cycling, rowing, etc.) is characterized by sustained, rhythmic movements that elevate heart rate and oxygen consumption, and is most known for its cardiovascular benefits Through consistent aerobic training, the heart becomes more efficient at pumping blood, leading to enhanced cardiac output and stroke volume [1]. This increased efficiency lowers resting heart rate and blood pressure, improving the cardiovascular system and all the veins and arteries that go with it [2].
Moreover, aerobic exercise triggers physiological adaptations within skeletal muscle. With regular endurance training, muscle fibers undergo mitochondrial biogenesis, resulting in a greater capacity for aerobic energy production [3]. Concurrently, improvements in capillary density enhance oxygen delivery to muscles, delaying the onset of fatigue during prolonged exercise [4]. Over time, these adaptations affect your VO2max (also a really hot longevity topic right now).
VO2max, or maximal oxygen consumption, represents the peak of your aerobic fitness, or your body's capacity to utilize oxygen during exercise. VO2max serves as a potent predictor of cardiovascular health, reflecting the efficiency of the heart and lungs in delivering oxygen to working muscles [5]. Defined as the maximum rate of oxygen consumption per unit of body weight, VO2max represents the interplay between respiratory, cardiovascular, and muscular systems [6]. Through targeted exercise aerobic interventions (and maybe even some types of resistance based training [7]), individuals can improve their VO2max, thereby enhancing their endurance capacity and bolstering their resilience against age-related declines in physiological function. (I posted about VO2max on instagram.)
The preservation of VO2max becomes essential to safeguarding overall health and wellbeing. A high VO2max is associated with myriad health outcomes, spanning cardiovascular resilience, skeletal muscle integrity, hormonal support, and cognition [8]. A higher VO2max value correlates with a reduced risk of ALL cardiovascular events, including myocardial infarction and stroke, underscoring the cardioprotective benefits conferred by aerobic fitness [9]. Individuals with elevated VO2max exhibit enhanced skeletal muscle health, characterized by greater mitochondrial density and oxidative capacity, helpful for resistance against sarcopenia and frailty in later years [10]. Hormonally, VO2max exerts a modulatory influence on endocrine function, promoting the secretion of growth factors and myokines that orchestrate tissue repair and metabolic regulation [11]. Moreover, emerging evidence suggests a symbiotic relationship between VO2max and cognitive function, with higher aerobic fitness levels correlating with preserved cognitive faculties and a reduced risk of neurodegenerative disorders, such as Alzheimer's disease and dementia [12].
What about resistance training?
By contrast, resistance training focuses on challenging the muscular system through the use of external weights or resistance bands, often at high loads (lots of weight) or high volume (lots of reps). As people engage in resistance exercises, they stimulate muscles via neuronal and growth pathways, promoting the development of muscle fibers and innervation [13]. Because muscle is the major sink for sugar and fat in our system, this increase in skeletal muscle mass contributes to overall metabolic health even when you’re not exercising [14], which may be one of the key predictors of healthy aging.
Furthermore, resistance training augments musculoskeletal strength and bone density, crucial factors in mitigating the risk of osteoporosis and age-related fractures [15]. By subjecting bones to mechanical stress, resistance exercises stimulate osteoblast activity, leading to the deposition of mineralized bone tissue [16]. This protective effect becomes increasingly pertinent for women in particular, as they navigate the hormonal fluctuations of menopause, which predispose them to bone loss [17].
Because of the implications of menopause to health outcomes such as metabolic and cardiovascular disease, muscle is particularly important for women to grow and preserve as they age. Beyond its metabolic perks, muscle acts as a reservoir for amino acids, facilitating the synthesis of vital proteins and hormones [18]. (Fun fact: your body uses about 400g of protein per day to replenish tissues, cells and enzymes. Given that you only eat about 100g per day, most of that protein is actually recycled in your body!) Skeletal muscle also produces myokines, signaling molecules that exert anti-inflammatory effects and modulate insulin sensitivity [19]. This dynamic interplay underscores the pivotal role of muscle in orchestrating metabolic homeostasis and warding off chronic diseases, including type 2 diabetes and cardiovascular disorders [20]. In one study done in (male) firefighters, maximal pushups was actually a better predictor of longevity than running capacity [21].
Moreover, the preservation of muscle mass and integrity holds profound implications for functional independence and quality of life. Sarcopenia, the age-related decline in muscle mass and strength, precipitates frailty and diminishes mobility [22]. This is particularly important for women, because muscle loss begins in the mid-thirties and can result in 1-5% of muscle lost yearly. And, the incidence of sarcopenia appears to be sex-specific with a recent longitudinal study indicating that females were at 20% higher risk of developing sarcopenia than males [22].
What about a “hybrid” training model?
The term “hybrid athlete” is getting a lot of press these days, basically meaning someone who does both aerobic and resistance training. Hopefully, it has become obvious that both have independent, and synergistic effects on the body! This “hybrid revelation” actually makes me laugh a bit, because the guidelines for exercise have been quite clear for the past almost 20 years: DO BOTH! The recommendations issued by the Physical Activity Guidelines state a goal of 150 minutes per week of moderate aerobic activity (or 75 mins of vigorous exercise) and at least two resistance training sessions per week. And, combining the cardiovascular enhancements of aerobic exercise with the muscular effects of resistance training, have shown an even greater reduction in disease risk and an enhancement of overall performance than either alone [23,24].
If you’re curious how to get started on a hybrid type of plan, I’ve written a really simple 5-day training protocol below that enhances all the combined physiologic benefits and meets all the current guidelines. I know there’s a lot of talk right now about targeted zone training, HIIT, and mobility, but honestly, all you need to do is keep it simple! Let me know what you think, and most importantly, enjoy!
An Optimal 5-Day Training Protocol
Day 1: Cardiovascular Intervals (50 min.)
30 minutes of brisk walking or cycling
20 minutes of interval training (alternating between moderate and vigorous intensity)
Day 2: Full Body Strength Training (30 min.)
Squats: 3 sets of 10 repetitions
Lunges: 3 sets of 10 repetitions (each leg)
Push-ups: 3 sets of 10 repetitions
Bent-over rows: 3 sets of 10 repetitions
Day 3: Active Recovery (20-60 min.)
Yoga or Pilates for flexibility, mobility and core strength
Day 4: Cardiovascular Endurance (30 min.)
30 minutes of swimming, rowing, cycling or steady state jogging
Day 5: Full-body Strength Training (45 min.)
Deadlifts: 4 sets of 8 repetitions
Bench press: 4 sets of 8 repetitions
Pull-ups or lat pulldowns: 4 sets of 8 repetitions
Overhead shoulder press: 4 sets of 8 repetitions
References
1. Myers J, Prakash M, Froelicher V, Do D, Partington S, Atwood JE. Exercise capacity and mortality among men referred for exercise testing. New England Journal of Medicine. 2002;346(11):793-801.
2. Cornelissen VA, Smart NA. Exercise training for blood pressure: a systematic review and meta-analysis. Journal of the American Heart Association. 2013;2(1):e004473.
3. Holloszy JO, Booth FW. Biochemical adaptations to endurance exercise in muscle. Annual Review of Physiology. 1976;38(1):273-291.
4. Green HJ, Jones S, Ball-Burnett M, Smith M, Huszczuk A, Ranney D. Adaptations in muscle metabolism to prolonged voluntary exercise and training. Journal of Applied Physiology. 1991;70(3): 925-931.
5. Noakes TD, Gibson ASC, Lambert EV. From catastrophe to complexity: a novel model of integrative central neural regulation of effort and fatigue during exercise in humans. British Journal of Sports Medicine. 2004;38(4):511-514.
6. Bassett Jr DR, Howley ET. Limiting factors for maximum oxygen uptake and determinants of endurance performance. Medicine & Science in Sports & Exercise. 2000;32(1):70-84.
7. Lundby C, Mazza O, Nielsen J, et al. Eight weeks of heavy strength training increases hemoglobin mass and V̇o2peak in well-trained to elite female and male rowers. J Appl Physiol (1985). 2024;136(1):1-12.
8. Myers J, McAuley P, Lavie CJ, Despres JP, Arena R, Kokkinos P. Physical activity and cardiorespiratory fitness as major markers of cardiovascular risk: their independent and interwoven importance to health status. Progress in Cardiovascular Diseases. 2015;57(4):306-314.
9. Laukkanen JA, Zaccardi F, Khan H, Kurl S, Jae SY, Rauramaa R. Long-term change in cardiorespiratory fitness and all-cause mortality: a population-based follow-up study. Mayo Clinic Proceedings. 2016;91(9):1183-1188.
10. Montero D, Lundby C. Refuting the myth of non-response to exercise training: 'non-responders' do respond to higher dose of training. The Journal of Physiology. 2017;595(11):3377-3387.
11. Pedersen BK, Febbraio MA. Muscle as an endocrine organ: focus on muscle-derived interleukin-6. Physiological Reviews. 2008;88(4):1379-1406.
12. Erickson KI, Voss MW, Prakash RS, et al. Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences. 2011;108(7):3017-3022.
13. Schoenfeld BJ, Peterson MD, Ogborn D, Contreras B, Sonmez GT. Effects of low- vs. high-load resistance training on muscle strength and hypertrophy in well-trained men. Journal of Strength and Conditioning Research. 2015;29(10):2954-2963.
14. Pratley R, Nicklas B, Rubin M, et al. Strength training increases resting metabolic rate and norepinephrine levels in healthy 50- to 65-yr-old men. Journal of Applied Physiology. 1994;76(1):133-137.
15. Latham NK, Anderson CS, Lee A, Bennett DA, Moseley A, Cameron ID. A randomized, controlled trial of quadriceps resistance exercise and vitamin D in frail older people: the Frailty Interventions Trial in Elderly Subjects (FITNESS). Journal of the American Geriatrics Society. 2003;51(3):291-299.
16. Vuori IM. Dose–response of physical activity and low back pain, osteoarthritis, and osteoporosis. Medicine & Science in Sports & Exercise. 2001;33(6):S551-S586.
17. Sowers M, Zheng H, Jannausch ML, et al. Amount of bone loss in relation to time around the final menstrual period and follicle-stimulating hormone staging of the transmenopause. Journal of Clinical Endocrinology & Metabolism. 2003;88(1): 2955-2958.
18. Volpi E, Mittendorfer B, Rasmussen BB, Wolfe RR. The response of muscle protein anabolism to combined hyperaminoacidemia and glucose-induced hyperinsulinemia is impaired in the elderly. The Journal of Clinical Endocrinology & Metabolism. 2000;85(12):4481-4490.
19. Pedersen BK. Muscle as a secretory organ: focus on muscle-derived interleukin-6. Physiological Reviews. 2008;88(4):1379-1406.
20. Srikanthan P, Karlamangla AS. Muscle mass index as a predictor of longevity in older adults. The American Journal of Medicine. 2014;127(6):547-553.
21. Yang J, Christophi CA, Farioli A, et al. Association Between Push-up Exercise Capacity and Future Cardiovascular Events Among Active Adult Men. JAMA Netw Open. 2019;2(2):e188341.
22. Cruz-Jentoft AJ, Bahat G, Bauer J, et al. Sarcopenia: revised European consensus on definition and diagnosis. Age and Ageing. 2019;48(1):16-31.
23. Schroeder EC, Franke WD, Sharp RL, Lee DC. Comparative effectiveness of aerobic, resistance, and combined training on cardiovascular disease risk factors: A randomized controlled trial. PLoS One. 2019;14(1):e0210292.
24. Collins KA, Fos LB, Ross LM, et al. Aerobic, Resistance, and Combination Training on Health-Related Quality of Life: The STRRIDE-AT/RT Randomized Trial. Front Sports Act Living. 2021;2:620300.