Strength
Episodes
Dr. Layne Norton and I discuss fat loss, resistance training, seed oils, the carnivore diet, artificial sweeteners, and much more.
In this clip, Dr. Martin Gibala discusses how functional training simultaneously boosts cardiorespiratory fitness and muscle conditioning.
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Exercise Nutrition Obesity Metabolism Muscle Polyunsaturated Fat Saturated Fat Time-Restricted Eating Protein Weight Loss Strength SupplementsDr. Layne Norton and I discuss fat loss, resistance training, seed oils, the carnivore diet, artificial sweeteners, and much more.
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In this clip, Dr. Martin Gibala discusses how functional training simultaneously boosts cardiorespiratory fitness and muscle conditioning.
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In this clip, Dr. Martin Gibala explains how vigorous activity activates both slow and fast-twitch muscles and the impact of aging on these fibers.
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In this clip, Dr. McGlory discusses the intriguing interplay between resistance training, nutrition, and muscle adaptation, especially among older adults.
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Dr. Chris McGlory discusses muscle protein dynamics, emphasizing how omega-3 helps maintain muscle mass in older adults.
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Dr. Rhonda Patrick answers audience questions on various health, nutrition, and science topics in this Q&A session.
Topic Pages
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High-Protein Diets
High-protein diets elevate amino acid availability, augmenting myofibrillar protein synthesis and hypertrophy, thereby facilitating strength gains.
News & Publications
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Exercise is one of the most effective ways to preserve physical function with age, but researchers are also testing whether drugs that target aging-related pathways can complement the body's adaptations to exercise. An exploratory trial tested whether sirolimus, also called rapamycin, could be timed around exercise in a way that supports function in older adults.
The study was a randomized, double-blind, placebo-controlled trial in 40 sedentary adults aged 65 to 85. Participants completed a 13-week home exercise program involving stationary cycling and chair stands (repeated sit-to-stand movements from a chair performed for 30 seconds) three times per week. They were assigned to receive either sirolimus, 6 milligrams once weekly, or a matched placebo, with the dose taken about 24 hours after the final weekly exercise session. Researchers measured chair-stand performance as the main outcome, along with grip strength, 6-minute walk distance, quality of life, C-reactive protein (CRP, a marker of inflammation), DNA methylation-based epigenetic age measures (estimates of biological age based on chemical tags on DNA), routine blood tests to monitor organ function, and adverse events.
- Both groups improved on the 30-second chair-stand test, but the sirolimus group tended to improve less, by about 2 fewer repetitions on average compared with placebo. This difference was too small and uncertain in the main analysis to know if it was real or just due to chance.
- In follow-up analyses that focused on participants who completed the study or closely followed the protocol, the gap became clearer. The sirolimus group performed about 2.5 to 3.4 fewer chair stands than the placebo group, and these differences clearly favored placebo.
- Other measures of physical function showed a similar pattern, with small differences favoring placebo, but none were strong enough to show a clear effect between groups. Grip strength was about 1.19 kg lower and walking distance about 4.87 meters shorter in the sirolimus group, while physical and mental quality-of-life scores also showed small differences.
- CRP did not show a consistent effect, and also the epigenetic age measures showed mixed results without a clear pattern.
- At least one adverse event was reported by 85% of participants in both groups. Even so, the sirolimus group had more adverse events overall (99 vs. 63), and more events the study team rated as possibly or probably treatment-related (35% vs. 15%).
Sirolimus has drawn interest in aging research because it inhibits mTORC1, one branch of the broader mTOR signaling network involved in nutrient and growth signaling. Constant high activity of mTORC1 signaling has been linked to shorter lifespan in animal studies, while more balanced activity is associated with better metabolic health. mTORC1 also plays an important role in muscle repair and adaptation after exercise, which creates a tension: suppressing it might support some aging-related processes while potentially interfering with training gains. This trial tested a timing strategy meant to separate these effects by spacing sirolimus away from the main post-exercise recovery and apdaption window. However, the findings suggest that the drug's long half-life may have allowed mTORC1 inhibition to persist into the next training sessions, potentially dampening the beneficial effects of exercise on physical function.
The main limitation is that this was a small, short trial, so the results are best viewed as an early signal rather than a final answer. Still, the findings suggest that weekly sirolimus may not pair well with exercise at this dose and schedule. In Q&A #40, I discuss potential longevity-related benefits and trade-offs of rapamycin.
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Strength training is a cornerstone of type 2 diabetes care, yet heavy lifting is not feasible for all patients. Researchers recently tested whether a modified approach, called blood-flow restriction training (BFRT), could deliver similar strength and metabolic benefits using much lighter weights.
The randomized study involved 20 inactive adults with type 2 diabetes who trained three times per week for 12 weeks. One group performed BFRT using about 30% of their one-repetition maximum (1RM, the heaviest weight a person can lift once). During each set, inflatable cuffs placed around the upper legs partially reduced blood flow. The comparison group performed conventional resistance training at about 70% of their 1RM without cuffs.
- Both training programs increased thigh muscle size and leg strength to a similar degree, even though the BFRT group used much lighter weights.
- Only the BFRT group showed clear improvements in skeletal muscle mitochondrial respiration, which reflects how effectively mitochondria generate cellular energy (ATP). The activity of citrate synthase, an enzyme used as a marker of mitochondrial content, also increased only in this group.
- Only the BFRT group improved mitochondrial respiration in fat tissue and reduced visceral fat, the fat stored deep in the abdomen around internal organs and strongly linked to insulin resistance and cardiovascular disease risk. In contrast, subcutaneous fat tissue volume decreased only after conventional strength training. Subcutaneous fat tissue lies just under the skin and is generally considered metabolically less harmful than visceral fat.
- Both groups experienced lower resting heart rate and lower diastolic blood pressure. Body mass index decreased modestly in both groups.
- Conventional training produced clearer improvements in aerobic fitness and blood triglyceride levels.
- Neither program clearly enhanced insulin sensitivity, reduced liver fat, or meaningfully altered key insulin signaling proteins in skeletal muscle.
Restricting blood flow during light exercise creates temporary local oxygen and energy stress, which makes the muscles respond as if they were lifting heavier loads. This stress may help explain the observed increases in AMPK and PGC-1α, key regulatory proteins of mitochondrial biogenesis, the process by which cells build new mitochondria. The training also increased signals linked to angiogenesis, the formation of new blood vessels, which may improve oxygen delivery to muscle and contribute to the observed improvements in mitochondrial function.
The findings suggest that people with type 2 diabetes can achieve important muscle and metabolic benefits without lifting heavy weights. Larger studies are needed to confirm whether this approach is effective and practical for broader clinical populations. In this clip, Dr. Brad Schoenfeld describes how blood flow restriction is used, its advantages, and its possible drawbacks.
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Age-related declines in muscle strength occur alongside rising burdens of heart disease and premature death, yet clinicians lack simple physical tests that identify the highest-risk patients. In a new study, a research team asked whether a quick measure that combines handgrip strength with body weight could help close this gap.
The investigators analyzed data from more than 10,000 U.S. adults and over 11,000 Chinese adults. They calculated a grip strength-to-weight ratio by adding the strongest reading from each hand and dividing it by the participant's body weight. Participants were grouped into four categories based on this ratio and followed for several years to track deaths. Cardiovascular disease was captured at the start of the study through standardized questions about previous medical diagnoses.
Here's what the researchers observed:
- Across both cohorts, adults in higher grip strength-to-weight quartiles had substantially lower rates of death from any cause than those in the lowest quartile, with the highest quartile showing a 73% lower risk in U.S. adults and nearly a 47% lower risk in Chinese middle-aged and older adults.
- In U.S. adults, the same pattern held for deaths from cardiovascular causes, with the highest quartile having a 79% lower risk than the lowest quartile.
- People in the higher quartiles had roughly a 30 to 40% lower prevalence of cardiovascular disease than those in the lowest quartile.
- In dose–response analyses, the risk fell sharply as the ratio increased from low values and then leveled off once a moderate level was reached, with protective effects beginning around 0.9 in the U.S. and 1.06 in China, and little further benefit beyond those points.
- When the U.S. cohort was divided by age and sex, grip strength-to-weight predicted mortality and cardiovascular disease only in adults aged 45 years and older, and associations tended to be stronger in men than in women.
These results suggest that the grip strength-to-weight ratio reflects aspects of muscle quantity and function that relate closely to cardiometabolic health. Skeletal muscle is a major site for glucose use and influences inflammatory signaling, so a low ratio may reflect poorer metabolic control and persistent low-grade inflammation, which in turn can promote cardiovascular events and early death.
The exclusion of people with missing grip strength or mortality data may have skewed the results, and differences in measurement protocols plus the observational design limit causal interpretation. Still, adding the grip strength-to-weight ratio as an inexpensive, non-invasive measure in routine clinical assessments could help clinicians identify higher-risk middle-aged and older adults who may benefit from strength training and other lifestyle interventions. Episode #78 of the FoundMyFitness podcast features a conversation between Dr. Brad Schoenfeld and me on using resistance training to improve strength, enhance body composition, maximize hypertrophy, and train efficiently.
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Combining collagen with resistance training enhances tendon strength, improving knee stability in middle-aged men. pmc.ncbi.nlm.nih.gov
Tendons are essential for force transmission between muscles and bones. However, as people age, tendons lose collagen and stiffen, impairing athletic performance and increasing injury risk. A recent study found that combining resistance exercise with collagen supplementation enhanced tendon health in middle-aged men.
Researchers investigated the effects of 12 weeks of resistance exercise and collagen supplementation on patellar tendon properties in 20 middle-aged men. Both groups engaged in progressive lower-body resistance training twice weekly and received either 30 grams of hydrolyzed collagen or a placebo after training. The researchers evaluated the participants' tendon size, stiffness, and strength before and after the intervention.
They found that participants who took collagen experienced a greater increase in patellar tendon cross-sectional area (+6.8 mm²) than the placebo group (+1.2 mm²). They also experienced a twofold greater increase in tendon stiffness and measures of tendon strength than the placebo group. Both groups experienced muscle strength and explosive power improvements, but tendon adaptations were more pronounced with collagen supplementation.
These findings suggest that 12 weeks of resistance training with collagen supplementation enhances patellar tendon properties in middle-aged men. The patellar tendon is a strong, fibrous connective tissue that connects the bottom of the kneecap (patella) to the top of the shinbone (tibia). It plays a crucial role in movements like walking, running, jumping, and squatting, as it helps control the movement and stability of the knee joint. Learn more about the benefits of collagen supplementation in our overview article.
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Resistance training in one arm can help preserve muscle strength and size in the opposite, immobilized arm, a phenomenon known as cross-education effects. journals.physiology.org
Injuries often leave one limb immobilized, driving a rapid decline in muscle strength and size. But what if training the opposite limb could help preserve the strength of the immobilized one? A recent study found that targeted exercise of one arm can help maintain strength and size in the opposite immobilized arm, offering potential benefits for rehabilitation.
Researchers immobilized the nondominant forearms of 16 adult participants for four weeks using a cast. Then, they randomly assigned them to a resistance training or non-exercising group. Participants in the training group performed eccentric wrist flexion exercises with the non-immobilized arm three times a week. Both groups underwent testing before and after the intervention to measure muscle strength, thickness, and cross-sectional area using ultrasound and computed tomography.
The researchers found that those in the training group experienced only a 2.4% reduction in strength in the immobilized arm compared to a 21.6% reduction in the non-training group. In addition, the training group saw a 1.3% increase in muscle size of the immobilized forearm, while the non-training group showed a 2.3% decrease. They also observed strength gains in the non-immobilized arm, with a 30.8% improvement in the training group compared to a 7.4% decline in the non-training group.
These findings suggest that engaging in targeted resistance training of the non-immobilized limb can help preserve the size of an immobilized limb and maintain strength across different types of muscle contractions. The researchers posited that the immobilized arm retained more muscle mass and strength due to neural adaptations from training the opposite arm, a phenomenon known as cross-education effects. Interestingly, sauna use can also help maintain muscle mass during periods of disuse due to immobilization. Learn more in our overview article.
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Declines in muscle force, power, and contractile function can be observed in older adults, clinical populations, inactive individuals, and injured athletes. Passive heating exposure (e.g., hot baths, sauna, or heated garments) has been used for health purposes, including skeletal muscle treatment. An acute increase in muscle temperature by passive heating can increase the voluntary rate of force development and electrically evoked contraction properties (i.e., time to peak twitch torque, half-relation time, and electromechanical delay). The improvements in the rate of force development and evoked contraction assessments with increased muscle temperature after passive heating reveal peripheral mechanisms’ potential role in enhancing muscle contraction. This review aimed to summarise, discuss, and highlight the potential role of an acute passive heating stimulus on skeletal muscle cells to improve contractile function. These mechanisms include increased calcium kinetics (release/reuptake), calcium sensitivity, and increased intramuscular fluid.
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Vitamin D supplementation may improve cardiorespiratory fitness and muscle strength (randomized controlled trial, n=74) pubmed.ncbi.nlm.nih.gov
From the abstract:
Cardiorespiratory fitness and muscle strength were measured before and after supplementation through maximal treadmill tests and dynamometry, respectively. Wilcoxon tests were used to compare intragroup results and the Mann-Whitney test to examine intergroup differences. There was an increase in the serum concentration of vitamin D in participants who ingested the supplementation. Cardiorespiratory fitness improved after supplementation through increases in the values of maximum oxygen consumption of 28% (p < .001). Muscle strength in left hand grip increased 18% in participants who received the supplement (p = .007). Sixty days of cholecalciferol supplementation improved cardiorespiratory fitness and upper limb muscle strength.
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Cardio exercise increases the production of FGF21 3x more than strength training: a hormone with relevance to metabolic disorders www.sciencedaily.com
From the article:
In a new study published in the scientific Journal of Clinical Investigation – Insight, the researchers show that cardio training on an exercise bike causes three times as large an increase in the production of the hormone FGF21 than strength training with weights. FGF21 has a lot of positive effects on metabolism.
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Endurance training on a bicycle has such a marked effect on the metabolic hormone that we know ought to take a closer look at whether this regulation of FGF21 is directly related to the health-improving effects of cardio exercise. FGF21’s potential as a drug against diabetes, obesity and similar metabolic disorders is currently being tested, so the fact that we are able to increase the production ourselves through training is interesting', Christoffer Clemmensen elaborates.
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Lifting weights for less than an hour a week may reduce your risk for a heart attack or stroke by 40 to 70 percent, according to a new study www.sciencedaily.com
Current public health guidelines recommend that adults engage in muscle-strengthening activities such as resistance training at least twice a week. Research indicates that resistance exercise provides a wide range of health benefits, including increased muscle mass and strength, greater bone density, and improved mood. Findings from a 2019 study also suggest that resistance exercise reduces the risk of the number one killer worldwide: cardiovascular-related disease and death.
The study involved more than 12,000 adults (average age 47 years) who were enrolled in the Aerobics Center Longitudinal Study - an ongoing prospective investigation of links between exercise and cardiovascular health. Participants underwent a comprehensive examination that included collection of a detailed medical history, assessment of cardiovascular and metabolic health parameters, and information-gathering about the participants’ resistance exercise habits.
They found that participants who engaged in resistance exercise one to three times (or a total of up to 59 minutes) per week were 40 to 70 percent less likely to experience a cardiovascular disease-related event than those who never engaged in resistance exercise. Engaging in resistance exercise more than four times (or more than an hour) per week did not confer any additional protection. The authors' analysis indicated that the decreased risk was due in part to resistance exercise’s effects on lowering body mass index, a known risk factor for cardiovascular disease.
These findings suggest that resistance exercise promotes cardiovascular health. Aerobic exercise is also important for cardiovascular health. Learn about the cardiovascular benefits of aerobic exercise in our overview article.
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From the article:
Muscle tissue can remodel itself, which is one reason why exercise becomes easier when we do it regularly, Lessard says. Over time, aerobic exercise such as running or swimming can alter muscle fibers to become more efficient at using oxygen during exercise. “We also grow new blood vessels to allow more oxygen to be delivered to the muscle, which helps to increase our aerobic fitness levels,” she says.
The scientists propose that high levels of blood sugar may prevent muscle remodeling in part by modifying the “extracellular matrix” proteins in the space between the muscle cells, where blood vessels are formed.
Adapting to aerobic exercise as though it were strength training:
The scientists found that these JNK pathway signals were getting crossed in the hyperglycemic mice, by activating pathways associated with strength training, even though the mice were performing aerobic exercise. “As a result, the muscles of hyperglycemic animals have bigger fibers and fewer blood vessels, which is more typical of strength training, rather than aerobic training,” Lessard says.
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Combining aerobic exercise and strength training may be the best strategy for improving healthspan. www.bmj.com
Current public health guidelines recommend that adults engage in regular physical activity for optimal health. Findings from a new study suggest that a combination of both aerobic and strength activities reduces the risk of death from all causes as well as specific causes.
According to the guidelines, adults should engage in at least 150 minutes of moderate-intensity aerobic physical activity or at least 75 minutes of vigorous-intensity aerobic physical activity each week, or an equivalent combination of both. They should also engage in muscle-strengthening activities of moderate or greater intensity on two days or more each week.
The population-based cohort study, which involved nearly 480,000 adults, drew on data from the National Health Interview Survey, an ongoing, cross-sectional survey of people living in the United States. The study participants reported how much leisure time aerobic and strength physical activity they engaged in each week. Then the authors of the study categorized them as having insufficient activity, aerobic activity only, strength activity only, and both aerobic and strengthening activities, based on the guidelines.
The authors found that the participants who engaged in recommended amounts of aerobic or muscle-strengthening activity had a lower risk of death from all causes, and these benefits were even greater if they engaged in both types of activities. They noted similar reductions in risk of death from cardiovascular disease, cancer, and chronic lower respiratory tract diseases.
These findings suggest that adherence to public health guidelines for exercise reduce the risk of disease and death and provide support for interventions to improve compliance.