There are 4 essential elements of physical fitness:

1. Cardiorespiratory fitness
2. Muscular fitness
3. Flexibility
4. Body composition

Cardiorespiratory Fitness

Cardiorespiratory fitness describes the ability of our heart, lungs, and circulation to supply oxygen and nutrients to the working muscles. It is enhanced by aerobic training, which involves activities that increase your heart rate and breathing such as walking, jogging, or biking. Working on this element of physical fitness improves your circulatory system by improving your ability to supply the body’s cells with oxygen and nutrients while removing carbon dioxide and metabolic waste. Aerobic exercise, which can help improve cardiorespiratory fitness, involves exercise lasting more than 2 minutes and can include either low- or high-intensity levels. Aerobic exercise increases heart and breathing rates to meet increased demands for oxygen in working muscles. Regular, moderate aerobic activity, about thirty minutes at a time for five days per week, can result in the increased efficiency of oxygen transport within the body, which strengthens the heart and reduces the risk of cardiovascular disease.^[1] Strengthening your heart muscle and increasing the blood volume pumped with each heartbeat will lead to a lower resting heart rate for healthy individuals. Aerobic exercise increases the ability of muscles to use oxygen for energy metabolism and therefore, create ATP.

Aerobic capacity, or VO₂ is the most common standard for evaluating cardiorespiratory endurance. VO₂ max is your maximal oxygen uptake, and the VO₂ max test measures the amount of oxygen (in relation to body weight) that you can use per minute. A test subject usually walks or runs on a treadmill or rides a stationary bicycle during this test. The volume and oxygen content of exhaled air is measured to determine oxygen consumption as exercise intensity increases. At some point, the amount of oxygen consumed no longer increases despite increases in exercise intensity. This value of oxygen consumption is referred to as VO₂ max, ‘V’ meaning volume, and ‘max’ meaning the maximum amount of oxygen (O₂) an individual is capable of utilizing.

Muscular Fitness

Muscular fitness includes both, muscular strength and endurance, which are developed and maintained by weight or resistance training. Building muscle mass is not just crucial for athletes and bodybuilders—building muscle strength and endurance is important for children, seniors, and everyone in between. The support provided by your muscles allows you to work, play, and live more efficiently. Strength training not only involves the use of resistance machines, resistance bands or free weights, but it can also involve the use of your own body weight when performing exercises. You do not need to pay for a gym membership or expensive equipment to strengthen your muscles. Homemade weights, such as plastic bottles filled with sand, can work just as well. You can also use your own body weight to do push-ups, leg squats, abdominal crunches, and other exercises to build your muscles. If strength training is performed at least twice a week, it can help improve muscle strength and increase bone strength. Strength training can also help you maintain muscle mass during a weight-loss program.^[2]

Flexibility

Flexibility is the range of motion available to your joints. Yoga, tai chi, Pilates, and stretching exercises improve this element of fitness. Stretching improves your range of motion and posture and helps you perform activities that require greater flexibility, such as chores around the house. In addition to working on flexibility, older adults should include balance exercises in their routine. Balance tends to deteriorate with age, which can result in falls and fractures.^[3]

Body Composition

Body composition is the proportion of fat and fat-free mass (which includes bones, muscles, and organs) in your body. A healthy and physically fit individual has a greater proportion of muscle and a smaller proportion of fat than an unfit individual of the same weight. Although habitual physical activity can promote a more healthful body composition, other factors like age, gender, genetics, diet, social determinants of health and weight stigma contribute to an individual’s body composition.

Physical Activity Recommendations: Canadian 24-Hour Movement Guidelines

The Canadian Society for Exercise Physiology (CSEP) has outlined physical activity guidelines for all age groups. Adults should get at least 150 minutes of moderate to vigorous-intensity aerobic physical activity each week. In addition to aerobic physical activity, it is recommended that adults perform muscle-strengthening activities on each major muscle group two or three times each week. CSEP also recommends that adults get 7-9 hours of good-quality sleep and limit sedentary behaviour to 8 hours or less per day by breaking up long periods of sitting as often as possible and having no more than 3 hours of recreational screen time per day.  To learn more about these guidelines, view the CSEP 24-Hour Movement Guidelines.