One of the fundamental truths in life is that humans are meant to move. Over the millennia, our ancestors lived active, mobile lives seeking, acquiring, or growing food and responding to challenges in the environment. Through this lens, it is not surprising that movement and exercise are critically important for all aspects of health and well-being. It is also not surprising to find that as our lives have become more sedentary, our overall health has decreased, and the number of people diagnosed with cancer has increased. The explanation for this lies in the link between movement, exercise, and metabolic health.
Although Sleep, Nutrition, and Stress & Emotional Health are very important, physical activity has the greatest impact on metabolic health. Regular exercise improves metabolic markers, such as blood pressure, lipid profile, blood glucose, and insulin sensitivity. Exercise can reduce visceral fat and increase muscle mass and muscle function, which are key factors determining insulin sensitivity and overall metabolic health. Exercise also has multiple beneficial effects on immune system function which improves resistance to infections and cancer.123
Improvements in cardiovascular and metabolic health provide many other health benefits. Regular physical activity is associated with an increase in life expectancy by up to 6.9 years due to the reduction in risk factors such as hypertension, diabetes, coronary heart disease, stroke, and cancer. Higher levels of cardiorespiratory fitness are linked to lower all-cause mortality, and even moderate levels of physical activity can significantly reduce the risk of premature death. Exercise improves the ability to perform daily activities (functional capacity) which is particularly important for older adults and those with chronic medical conditions. Dynamic aerobic and resistance exercises enhance functional tests such as VO2 max and walking tests, which are critical for overall physical health and activity.12345
Let’s explore the basic techniques of exercise and how you can incorporate them into your life.
Types of Exercise
Exercise mainly falls into two categories: cardiovascular, which improves heart and lung function, and resistance, which builds muscle strength. Both types are important for overall health and can help reduce cancer risk.
Exercise may be characterized by the primary organ systems being trained and the intensity of the effort. The two major categories of exercise are cardiovascular and resistance training:
Cardiovascular Exercise seeks to increase the capacity of the heart and lungs to deliver oxygen and energy to the body, or cardiorespiratory fitness. This is achieved by increasing the amount of blood the heart can pump, (cardiac output), and the ability of tissues to extract oxygen from the blood (oxygen uptake). When physical activity increases, cardiac output and oxygen uptake increase. Over time, adaptations occur that improve the ability of the body to perform these functions. Examples of cardiovascular training include walking, running, bicycling, and swimming.
Resistance Exercise increases muscle strength and size by exerting force on the muscles. This leads to adaptations that increase the size, strength, and metabolic capacity of the muscle. Examples of resistance training include weight lifting and bodyweight exercises such as calisthenics (e.g., push-ups, pull-ups, and bodyweight squats), pilates, and yoga.
Exercise can also be used to improve functional capacity by increasing flexibility (the range of motion of the musculoskeletal system) and proprioception (balance). Along with strength, these factors are the determinants of stability, which is critically important to maintaining functional capacity and minimizing the risk of injury and falls, especially in older individuals. Exercises that train these systems are important to health and well-being, but do not increase cardiorespiratory fitness, strength, or metabolism directly. Therefore, we will focus primarily on cardiovascular and resistance training and discuss each of these in more detail in the next sections.
Cardiovascular Exercise
Cardiovascular exercise improves heart and lung function. Low-intensity exercise enhances your body’s energy efficiency, while high-intensity exercise boosts overall fitness. Both types can help reduce cancer risk and improve outcomes for cancer patients.
Cardiovascular exercise or training describes physical activity that increases cardiovascular and respiratory function and performance. This typically involves a movement or muscular activity that increases the metabolic activity of muscles, and increases cardiac output, respiration, oxygen, and nutrient delivery to the muscle. This results in many beneficial adaptive responses in the cardiovascular system and other organs in the body.6 Cardiovascular exercise can be divided into several levels of intensity that result in different metabolic effects:
Low-intensity, or zone 2 cardiovascular exercise, primarily improves the ability of cells to utilize oxygen and fuels, referred to as aerobic efficiency. This type of exercise enhances the capacity of skeletal muscles to use oxygen to produce energy (oxidative capacity). This occurs through adaptations that increase the ability of muscle to take up glucose and increase the number and function of mitochondria in muscle cells, which increases their capacity to utilize both glucose and fatty acids. These adaptations are crucial for improving overall metabolic health and reducing the risk of metabolic diseases such as type 2 diabetes and cardiovascular disease. Zone 2 exercise also helps in maintaining a lower resting heart rate and blood pressure, which are indicators of improved cardiovascular health.156
High-intensity (zone 3-5) cardiovascular exercise primarily improves the ability of the heart and lungs to deliver oxygen to tissues, called maximal aerobic capacity or VO2max. VO2max is a critical measure of cardiorespiratory fitness and is associated with a lower risk of cardiovascular events and all-cause mortality. High-intensity exercise leads to improvements in cardiac output (the volume of blood the heart can pump in one minute), stroke volume (the amount of blood the heart can pump with each heartbeat), and pulmonary ventilation (the amount of oxygen taken in by the lungs every minute). It also enhances the body’s ability to metabolize and clear lactate, which allows for sustained high-intensity efforts.156
Both types of cardiovascular exercise provide significant benefits to cancer patients and should be a part of their health optimization practices. Current evidence also demonstrates that more physical activity reduces the risk of cancers of the bladder, breast, colon, endometrium, esophagus, kidney, stomach, and lung. For people with colorectal cancer, women with breast cancer, and men with prostate cancer, greater amounts of physical activity are associated with reduced risk of mortality from the original type of cancer. For people with colorectal cancer or women with breast cancer, greater amounts of physical activity are associated with reduced risk of all-cause mortality.7 Regular physical activity has been shown to improve cardiorespiratory fitness, reduce cancer-related fatigue, and enhance quality of life in cancer patients. Exercise interventions can mitigate the toxic effects of cancer treatments such as chemotherapy and radiation, by improving cardiovascular function and metabolic health.78910
Resistance Exercise
Resistance exercise builds muscle strength and size, which improves overall metabolism. It increases muscle mass, enhances insulin sensitivity, and can help reduce body fat. These benefits can lower the risk of metabolic and cardiovascular diseases.
Resistance exercise or resistance training (RT) involves muscle contraction against external resistance, leading to various physiological adaptations. These adaptations can be categorized into muscle fiber responses and neuromuscular responses.
Resistance training induces muscle hypertrophy, which is the increase in the cross-sectional area (CSA) of muscle fibers. This occurs due to an increase in the size of existing muscle fibers (hypertrophy) and, to a lesser extent, the formation of new muscle fibers (hyperplasia). RT can cause a shift in muscle fiber types, particularly from type I (slow-twitch) to type IIa (fast-twitch) fibers, which are more suited for strength and power activities. RT stimulates muscle protein synthesis through mechanical tension, metabolic stress, and limited damage to the muscle cells, which leads to muscle repair and growth.111213
The muscular adaptations to resistance training have multiple important metabolic benefits. RT increases muscle mass, which raises the RMR. This is because muscle tissue is much more metabolically active than other tissues and requires more energy at rest. RT enhances insulin sensitivity due to both increased muscle mass and improved glucose uptake by muscles. RT helps reduce body fat, particularly visceral fat. This reduction is due to increased energy expenditure and improved metabolic function. wBy improving body composition, insulin sensitivity, and lipid profiles, RT reduces the risk of metabolic syndrome and cardiovascular disease.121415
Resistance Training Options
Resistance training includes bodyweight exercises, yoga, and weight training. Free weights offer versatility and functional strength benefits but require proper technique. Weight machines are safer and easier to use, especially for beginners, but may limit range of motion and are less practical for home use.
Types of Resistance Training
Resistance training includes body weight exercises such as calisthenics and isometric exercises such as pilates and yoga, and weight training. Most resistance training options include some low intensity cardiovascular exercise, flexibility and balance training. Yoga and pilates offer an excellent combination of low intensity resistance training and stability that can be an important part of exercise routines. The most potent form of resistance training is weight training, as this provides the potential for much higher muscle loads which result in greater muscle hypertrophy and adaptations. Weight training can be accomplished with free weights, weight machines, or a combination of both. Let’s review the basics of weight training and discuss the advantages and disadvantages of the different options to help structure an effective and individualized weight training program.
Free Weights
Free weights include barbells, dumbbells, barbells, and kettlebells. They allow for a wide range of exercises and movements, making them highly versatile. They mimic real-life movements and engage stabilizer muscles, improving overall functional strength and coordination. Free weights allow for a full range of motion, which enhances flexibility and joint mobility. They are generally less expensive and more space-efficient than machines, making them ideal for home gyms.
Free weight exercises require proper technique and form to avoid injuries, which can be challenging for beginners. Some exercises, especially those involving heavy weights, may require a spotter for safety. There is a learning curve to free weight exercises, so beginners may need guidance to learn the correct form and techniques.
Weight Machines
Machines provide guided movements, reducing the risk of injury and making them safer for beginners. They allow for the isolation of specific muscle groups, which can be beneficial for targeted training. Machines are generally easier to use and require less precise technique, making them accessible for all fitness levels. A spotter is generally not required with weight machines, allowing for safer solo workouts.
Some machines restrict the range of motion and do not engage stabilizer muscles as effectively as free weights, which may limit functional strength gains. Machines are more expensive and require more space than free weights. This makes them less practical for home training and usually requires a gym membership for access.
Basics of Weight Training
Resistance training targets various muscle groups using different exercises. Compound exercises work multiple muscles, while single muscle exercises focus on specific areas. Training involves sets and repetitions with varying weights. The optimal approach depends on your goals: strength, muscle growth, or endurance.
There are many muscles of different sizes throughout the body. They typically work in groups to perform specific movements of different body areas. Different exercises work different muscle groups, so it is important to know the major muscle groups that can be trained and the exercises used to train each muscle group.
Muscle Groups
- Chest: Pectoralis major and minor
- Back: Latissimus dorsi, trapezius, rhomboids
- Shoulders: Deltoids
- Arms: Biceps, triceps, forearms
- Legs and Hips: Quadriceps, hamstrings, gluteals, calves
- Core: Abdominals, obliques, lower back
Basic Exercises for each Muscle Group
- Chest: Bench press, push-ups, chest fly
- Back: Pull-ups, pull downs, rows, shrugs
- Shoulders: Shoulder press, lateral raises, front raises
- Arms: Bicep curls, tricep extensions
- Legs and Hips: Squats, leg press, deadlifts, hip extensions, leg extensions, leg curls, calf raises
- Core: Planks, crunches, twists, leg raises, back extensions
Compound vs. Single Muscle Exercises
Compound exercises engage multiple muscle groups and move multiple joints. Examples include squats, deadlifts, bench press, shoulder press, and pull ups. They train multiple muscle groups simultaneously and are efficient for building overall strength and muscle mass. They also mimic functional activities such as standing and walking more directly. Single muscle exercises target a specific muscle group and move only one joint. Examples include bicep curls, tricep extensions, leg extensions and leg curls. They are useful for isolating and strengthening specific muscles. Most weight machines are single muscle exercises.
Sets, Repetitions and Weight
Resistance exercises are defined by the number of times each exercise is done (sets), the number of times the movement is repeated in each set (repetitions or reps), and the resistance or load applied to the muscle (weight). The maximum amount of weight that can be lifted for one repetition of a particular exercise with good form is the one repetition maximum (1RM). The 1RM is used to determine the appropriate weight for training each exercise. Resistance training sessions are typically structured by the number of sets, reps, and weight (expressed as a percentage of 1RM).
Recommended Repetitions, Sets and Weight
- Strength: 4-6 reps, 3-5 sets, 85-100% of 1RM
- Hypertrophy (Muscle Growth): 8-12 reps, 3-4 sets, 70-85% of 1RM
- Endurance: 12-20 reps, 2-3 sets, 50-70% of 1RM
Optimal Frequency and Recovery
- Frequency: Each muscle group should be trained 2-3 times per week for optimal results.
- Recovery Time: Recovery time between sets varies based upon intensity, but is typically 1-3 minutes. Allow 48-72 hours of rest between training sessions for the same muscle group to ensure adequate recovery and muscle growth.
Strength Training and Cancer
*Strength training may help reduce cancer risk and improve outcomes for cancer survivors. It can lower overall mortality risk and help manage treatment side effects.
The link between overall physical activity / cardiovascular exercise and decreased cancer risk is well defined, the link between resistance training and cancer risk is less studied. A systematic review and meta-analysis of epidemiology studies found that muscle-strengthening activities were associated with a 13% lower total cancer mortality.16 Another study found that resistance training was associated with a 33% reduction in all cause mortality in cancer survivors.17 Resistance training was associated with lower risk of bladder and kidney cancers, but not overall cancer risk in a large prospective cohort study.18 Resistance exercise at least 1 day per week was associated with reduced risk of all-cause mortality in cancer survivors.19 Resistance training can help manage side effects of cancer treatment like loss of muscle strength, fatigue, neuropathy, and reduced quality of life. A prospective study showed that high-intensity strength training improved muscle strength, cardiopulmonary function, and quality of life measures in cancer survivors.20
There is growing evidence that resistance training and other forms of exercise can reduce cancer risk, improve survival after diagnosis, help manage treatment side effects, and enhance quality of life in cancer patients and survivors. More research is still needed on optimal exercise prescriptions for different cancer types and clinical situations.
Summary and recommendations
Regular exercise, combining cardiovascular and strength training, can significantly reduce cancer risk and improve outcomes for cancer survivors. Aim for at least 150 minutes of moderate exercise weekly, including strength training twice a week, but start at your current fitness level and consult your medical team for a personalized plan.
The available evidence suggests a strong association between physical activity and the risk of developing cancer, cancer recurrence, treatment related side effects, quality of life, and survival. These effects are mediated by an interrelated group of beneficial changes in cardiorespiratory fitness, aerobic efficiency, glucose metabolism and immune function. These benefits are best defined for cardiovascular exercise, but also apply for resistance training. Optimal health effects are achieved with combined cardiovascular and resistance exercise. For these reasons, all cancer patients and those at risk should strongly consider adopting a regular exercise program. The key question is how to start and what exercise program should be used?
The answer to this question is complex and will vary based upon your baseline fitness level, body composition, and any physical limitations that you have based upon cancer treatment or other chronic diseases. An individualized program should be developed in collaboration with your medical team, but we can provide some suggestions that will help frame that discussion.
The good news is that even small improvements in physical activity can have a major impact upon your cardiometabolic health. If you are sedentary and do not currently exercise, starting a walking program can have significant benefits. Start at your level of tolerance and increase the pace and length of your walks up to 150 minutes a week. As your fitness increases, add zone 2 cardiovascular training, more vigorous cardiovascular exercise such as high intensity interval training, and resistance training. The target for adults with no major cardiopulmonary or physical limitations should be to meet the minimum level of exercise recommended by the Department of Health and Human Services (DHHS) Physical Activity Guidelines, summarized below:
DHHS Physical Activity Guidelines, 2018:7
Moderate intensity cardiovascular exercise: (3-6 mets, e.g. brisk walking and zone 2 training) 150-300 minutes per week. OR
Vigorous intensity cardiovascular exercise: (>6 mets, e.g. jogging, running, exercise classes HIIT) 75-150 minutes per week.
Resistance exercise: (weight training, calisthenics) Train each muscle group at least twice a week. The duration of training is not specified.
Exercise not meeting the minimum duration or intensity is still beneficial; even brief periods of movement are beneficial. Sitting is discouraged.
The exact type of exercise chosen from each category can vary based upon the individual’s preferences, level of fitness, access to fitness equipment and any physical limitations. Once cleared by your medical team, a personal trainer or coach can be helpful in designing an exercise program, providing education of form, reviewing progress, and making changes as needed. Evidence suggests that varying your exercise program from time to time may provide better adaptations and minimize the boredom that comes from a static routine. On the other hand, consistency in completing your exercise plan is a key to getting the most health benefits over the long term.
Footnotes
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Warburton, D. E. R., & Bredin, S. S. D. (2012). Health benefits of physical activity: the evidence. NCBI. ↩ ↩2 ↩3 ↩4
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Gremeaux, V., Gayda, M., Lepers, R., Sosner, P., Juneau, M., & Nigam, A. (2012). Exercise and longevity. ScienceDirect. ↩ ↩2
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Harvard Health Publishing. (2019). Can exercise extend your life? Harvard Health. ↩ ↩2
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American Heart Association. (2006). Assessment of Functional Capacity in Clinical and Research Settings. AHA Journals. ↩
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NCBI. (2024). Physical Exercise to Improve Functional Capacity. NCBI. ↩ ↩2 ↩3
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Cardiovascular Effects and Benefits of Exercise - PMC - NCBI ↩ ↩2 ↩3
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https://health.gov/sites/default/files/2019-09/PAG_Advisory_Committee_Report.pdf ↩ ↩2 ↩3
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Current Evidence on the Benefit of Exercise in Cancer Patients ↩
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Exercise, cancer and cardiovascular disease: what should clinicians … ↩
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The benefits of exercise in cancer patients and the criteria for … ↩
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https://ijbnpa.biomedcentral.com/articles/10.1186/s12966-021-01142-7 ↩
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https://www.mayoclinicproceedings.org/article/S0025-6196%2814%2900717-4/fulltext ↩