Physical inactivity is now identified as the fourth leading risk factor for death globally, accounting for about 6% of the total deaths worldwide. Physical inactivity levels are rising globally, spanning all economic, educational and age strata. This has major implications for the general health of the people worldwide and for the prevalence of lifestyle diseases such as cardiovascular diseases (coronary heart disease and stroke), diabetes and cancer, and their risk factors such as raised blood pressure, raised blood sugar and overweight. Physical inactivity, i.e. lack of exercise, is estimated as the principal cause for approximately 21-25% of breast and colon cancer burden, 27% of diabetes and approximately 30% of coronary artery diseases (which can ultimately lead to heart attack). As per WHO, of the 56.9 million deaths globally in 2016, 40.5 million or 71% were due to lifestyle diseases. You can read about the total burden of these diseases in my post Chronic Diseases: the Silent Killers.
Global health is being influenced by three trends: globalisation, urbanisation, and population ageing.
Though globalisation has had many beneficial effects on health and medical care, one negative health-related effect of globalisation is a trend known as “nutrition transition”. As a result of this, the population in low- and middle-income countries are now consuming diets high in total energy, fats, salt and sugar (so-called fast foods).
Urbanisation is increasing rapidly. Today, 55% of the world’s population lives in urban areas. In 1950, 30% of the world’s population was urban and by 2050, 68% of the world’s population is projected to be urban. Close to 90% of this increase will take place in Asia and Africa. Together, India, China and Nigeria will account for 35% of the projected growth in the world’s urban population between 2018 and 2050. Now, how does urbanisation add to the risk of lifestyle diseases? Urbanisation creates conditions in which people are exposed to new products, technologies and the marketing of unhealthy goods, and in which they adopt less physically active types of lifestyle. Rapid unplanned urban sprawl with no grounds, parks and stadiums has reduced opportunities to be physically active. Lack of dedicated safe cycling tracks and footpaths along the roads and the traffic conditions have rendered roads unsafe for active methods of travelling, such as walking or cycling.
Due to improved living conditions and health care, rapid population ageing is occurring worldwide. According to a 2017 report from UN, the number of older persons – those aged 60 years or over – is expected to more than double by 2050 and more than triple by 2100, rising from 962 million globally in 2017 to 2.1 Billion in 2050 and 3.1 billion in 2100. Globally, the population aged 60 or over is growing faster than all younger age groups.
The above underlying socioeconomic, cultural, political and environmental factors result in unhealthy environments and behaviours (unhealthy diets and excessive energy intake, physical inactivity and tobacco use) and are shaping health conditions everywhere. Lifestyle diseases, long considered the close companions of affluent societies have changed places. Diseases once associated with abundance are now heavily concentrated in poor and disadvantaged groups. These diseases now impose their greatest burden on low- and middle-income countries, where most of the world’s population lives. As per WHO, in 2016, out of the 40.5 million deaths globally on account of lifestyle diseases, 31.5 million or 78% occurred in low- and middle-income countries. Each year 15 million people die from lifestyle diseases between the ages of 30 and 69 years; over 85% of these “premature” deaths occur in low- and middle-income countries.
However, what is encouraging is that regular participation in physical activity has been shown to reduce the risk of cardiovascular diseases, diabetes, hypertension, colon cancer, breast cancer and depression. In addition, physical activity is a key factor which influences energy expenditure and thus is fundamental to energy balance and weight management. You can read about obesity, including normal weight obesity, and complications of obesity in my earlier posts on the subject.
In my post, Health benefits and risks associated with physical activity, I had discussed various health benefits associated with physical activity. Exercise is the cornerstone of any lifestyle modification aimed at reducing the prevalence of lifestyle diseases. The ability of exercise to restore function to organs, muscles, joints, and bones cannot be matched by any drugs or surgery. However, to derive optimal health benefits from exercise, an exercise program needs to follow certain parameters, similar to drug prescription, such as frequency, dose (amount), time (duration) and type (of physical activity). Keeping in view the importance of proper prescription of exercise for optimal health and fitness benefits, the American College of Sports Medicine (ACSM) and the American Medical Association (AMA) co-launched a global health initiative – ‘Exercise is Medicine’ (EIM). EIM is committed to the belief that physical activity promotes optimal health, is integral in the prevention and treatment of many medical conditions, and should be regularly assessed and included as part of health care. EIM urges healthcare professionals to assess the physical activity levels of their patients at every visit, provide physically inactive patients with brief counselling and ‘write’ a basic exercise prescription, or refer patients to a qualified exercise professional.
In 2010, WHO has developed Global Recommendations on Physical Activity for Health. The primary focus of these recommendations is primary prevention (intervention before health effects occur, through measures such as vaccination, altering risky behaviours [poor eating habits, physical inactivity, tobacco use], and banning substances known to be associated with a disease or health condition) of lifestyle diseases through physical activity at population level.
In my post on health benefits of exercise, referred to above, I have discussed the various components of physical fitness (viz. cardiorespiratory or aerobic endurance, muscular fitness, flexibility and body composition), and the benefits of these on health. However, before discussing the principles of exercise prescription individually for these components of physical fitness, it is imperative to first understand the various factors used for exercise prescription, the components of an exercise training session and finally, the general principles which govern the outcome of an exercise program. Thereafter, in my succeeding posts, I will be discussing exercise prescription individually for the improvement of cardiorespiratory (or aerobic) endurance, muscular fitness and flexibility.
‘Exercise is good medicine’, is now well accepted by the health community. To improve your fitness, its crucial to not only monitor if you are doing enough but also to make sure you don’t overtrain. When we think of ‘medicine’, we often think of a drug, something to be taken by mouth or injection. Although not ‘taken’ but done, an exercise prescription is much like a drug prescription.
In accordance with the training ‘principle of individual differences’, which will be discussed below, exercise prescription is individually designed to meet the patient’s health and physical fitness goals, keeping in view the patient’s present health and fitness status, and factors like physical and social environment. As the individual fitness goals may vary widely, guidelines advocated in this post are primarily limited to prescribing exercise for the apparently healthy adults, whose goal is to improve physical fitness and health. Individuals engaged in recreational or competitive sports will require more advanced training techniques which are beyond the scope of this post. The exercise prescription guidelines are in consonance with the WHO’s Global Recommendations on Physical Activity for Health, published in the year 2010.
When prescribing exercise, the total physical fitness of the individual and not just the aerobic fitness must be considered. A well-balanced fitness program should incorporate all ‘health-related components of physical fitness discussed above viz. cardiorespiratory (aerobic) endurance, muscular fitness and flexibility training. The neuromotor exercise training or skill-related components of physical fitness such as balance, coordination, and agility are particularly useful for older adults to improve or maintain physical function and to decrease the risk of falls, which are a major cause of serious injuries, including fractures, in the elderly. However, unlike health-related components of physical fitness, there are no universally accepted definitive recommendations for the amount of neuromotor exercise training required for optimum benefits. Certain activities such as Tai Chi and Yoga which combine resistance, flexibility and neuromotor exercises, may be particularly beneficial and easier to incorporate into a physical fitness program in older people, for improvement of neuromotor fitness.
Factors used to formulate exercise prescription
To be maximally effective for therapy or health enhancement, the following factors must be considered when prescribing exercise:
F ~ Frequency (i.e. how often)
I ~ Intensity (i.e. how hard)
T ~ Time (i.e. how long)
T ~ Type (mode or what kind)
V ~ Volume (i.e. amount)
P ~ Progression (i.e. advancement in exercise intensity, volume etc.)
These factors can be summarised by the acronym FITT-VP.
Components of exercise session
An exercise session should ideally have the following components:
- Conditioning/sports phase
Pre-workout warm-up is the foundation of an exercise program as it prepares the body and the mind for the more intensive physical activity that is to follow. Warm-up is critical for better performance and prevention of injuries. The warm-up broadly has three components – general warm-up, joint mobility or stretching exercises and sport-specific activity. General warm-up involves doing light aerobic exercises such as jogging or skipping and is colloquially known as ‘pulse raiser’. It pumps-up the cardiorespiratory system, increasing the blood flow and oxygen supply to the whole body, raises the body’s temperature and ‘loosens up’ the muscles.
Warm-up stretches or joint mobility exercises should be performed after the general warm-up, as by then the muscles are warmer and more elastic, allowing us to stretch further than we normally would. Stretch the muscles to the point where you can feel a stretching sensation in the muscle belly. Hold this position for 20 to 30 seconds; if the stretching sensation fades in this time, move a little further into the stretch until you can feel it again. After 20 to 30 seconds, relax the muscle and then repeat, trying to move the joint further into its range. Again, hold for 20 – 30 seconds. Stretching improves the range of motion of the joints and muscles thereby reducing the risk of injuries.
Before the conditioning/sports session, it is always a good idea to perform a warm-up which is most similar in terms of movement patterns to the activity/sport you are preparing for. This allows the body to prepare for the specific demands of the activity ahead. Sports-specific warm-up involves rehearsing lighter or toned-down version of the common movement patterns and skills which will be used in the conditioning/sport ahead. For e.g., if you are a runner, a light jog is the best warm-up; if you are about to lift weights, do a few lifts with a light weight; if you are doing martial arts training, the sports-specific warm-up should include a few light kicks and punches.
Depending on your athletic proficiency and the intensity of the conditioning session, the warm-up should last at least 5 to 10 minutes; however, it may extend up to up to 30 minutes. The duration of the warm-up will also vary depending on the ambient temperature; colder weather necessitating longer warm-up. Do not warm-up too early; the benefits are lost after about 30 minutes of inactivity.
Conditioning and/or sports-related activity
This phase includes aerobic, resistance, flexibility and neuromotor exercise and/or sporting activity. This portion of your workout will vary greatly from person to person and goal to goal. The specifics of the various conditioning programs will be discussed in details in the succeeding posts.
During a strenuous workout, your body goes through a number of stressful processes and waste products accumulate in the working muscles. The cool-down after the conditioning phase enables gradual recovery of heart rate, and blood pressure and helps remove waste products, such as lactic acid, from the working muscles. Abruptly stopping exercise poses two risks. Firstly, during exercise, to meet the increased requirements of the working muscles for blood supply, the blood vessels dilate. During exercise, contractions of the working muscles act like a pump and squeeze the blood through the veins, helping it to return to the heart. Once the exercise ceases, it takes some time for the veins to return to their normal size. Also, after the exercise is over, heart rate falls rapidly and also the muscles relax and no longer exert the pumping action on the veins. Combined together, these changes can result in the pooling of blood in the veins of the legs. This venous pooling can result in a fall in the blood pressure, making a person feel dizzy. Secondly, following cessation of exercise, the working muscles need increased blood flow for the removal of the waste products accumulated during the exercise/physical activity. However, if the physical activity ceases abruptly, the heart rate falls down rapidly resulting in a rapid reduction of the blood circulation and delay in the removal of the waste products from the working muscles. This predisposes the working muscles to a higher risk of injuries, particularly muscle soreness. Cooling down after a workout is easy because it closely resembles warming-up. Do some light exercise such as jogging or walking followed by stretching of the muscle groups trained during your workout. The cool-down period usually lasts about 5 to 10 minutes.
Flexibility is an important component of physical fitness and flexibility can be improved by stretching exercises. Stretching to improve flexibility is distinct from the warm-up and cool-down phases. Warmer muscles exhibit a high degree of elasticity and thus are more amenable to stretching. Therefore, stretching may be done either following the warm-up or cool down.
Before discussing the prescription of exercise training for aerobic endurance, muscular fitness and flexibility exercises based on FITT-VP factors, some cardinal principles of physical fitness training will be discussed.
Principles of physical fitness training
Following cardinal principles of physical training determine the outcome of an exercise program and must be adhered to while formulating an exercise training program.
Principle of regularity
In order to produce a training effect, physical fitness training should be done regularly. The in-frequent schedule can do more harm than good.
Principle of individual differences
Each human being is an individual with unique skills and abilities; consequently, all individuals do not respond similarly to a given training stimulus i.e. there will be inter-individual variations in the degree of response to similar training regimens. In addition, each individual’s relative fitness level at the start of a training program may vary, which will also influence the result of a training program. Individuals with low levels of baseline fitness will show the greatest training improvements whereas well-conditioned individuals will show only minimal improvement. This principle is equally applicable to healthy individuals as well as those with cardiovascular disease or at high risk for the disease.
A practical implication of this is that a group of individuals starting on a similar training program will show varying improvements in physical fitness or exercise performance after a set duration. Therefore, for optimum training benefits to occur, exercise prescription should take into account individual needs and capacities, rather than prescribing the same exercise program for everyone.
Principle of adaptation
Adaptation is the process body goes through to better meet the demands placed on it. Adaptation is the way the body ‘programs’ muscles to remember activities, movements or skills. By repeating that skill or activity, the body adapts to the stress and activity becomes easier to perform.
Principle of recovery
The recovery principle states that you must allow time for adaptations to take place. Without proper time for recovery, fatigue, overtraining, and injury could result.
Principle of specificity
This principle states that adaptations in metabolic and mechanical functions are specific to and depend on the intensity, duration, frequency and mode of overload imposed. The metabolic specificity pertains to the energy systems that are used during the activity whereas mechanical specificity pertains to the muscles used in that activity. For instance, a specific intense workload of short duration, as in strength/power training, will produce specific strength/power adaptations in the specific energy pathways as well as the muscles involved. Similarly, specific endurance training elicits specific aerobic system adaptations.
In simple terms, specific exercise elicits specific adaptations (both metabolic as well as mechanical) that results in specific performance improvements. Therefore, a runner should train by running and a swimmer should train by swimming. However, a limited transfer of benefits between strength/power and aerobic training does take place.
Principle of variety
By choosing a variety of exercises within the limits of specificity, certain muscles are allowed more time for recovery from a particular exercise. Also, a variety of exercises may help to prevent staleness and boredom from doing the same activity repeatedly.
Principle of overload
Exercising at an intensity greater than normal stimulates highly specific adaptations so the body functions more efficiently. Regular application of a specific exercise overload enhances physiologic functions which result in improved exercise performance. The overload can be achieved by manipulating the various factors utilised for exercise prescription such as frequency, intensity and duration or a combination of these.
Principle of progression
Principle of progression is an extension of the overload principle and states that workload should be increased progressively for improvements to continue, till the desired goal is achieved. A conditioning program should begin at a tolerable level of exercise and progress in intensity and volume towards a targeted goal for the individual. However, there should be an optimal time frame for this overload to occur. If the overload is increased too rapidly, not allowing enough time for recovery to take place, it will result in exhaustion and injury. On the other hand, if the overload is increased too slowly, improvement is unlikely.
The principle of overload is not applicable only to competitive athletes; in fact, the concept of individualised and progressive overload applies equally to sedentary persons and even cardiac patients participating in an exercise-based cardiac rehabilitation program.
Principle of reversibility
This principle states that when a person stops participating in regular physical activity, detraining i.e. loss of metabolic and mechanical adaptations occurs rapidly. By the end of 1 or 2 weeks only, there may be a significant reduction in both metabolic and exercise capacity and most of the training improvements may be gradually totally lost within a few months. Even among highly trained athletes, beneficial effects accruing from many years of prior training are lost on discontinuing training. In brief, the principle implies “use it or lose it.”
Physical inactivity is now identified as the fourth leading risk factor for death globally. Physical activity levels are rising globally with major implications for the prevalence of lifestyle diseases and the general health of the population worldwide. As a result, an average person will spend his/her last 10 years of life in sickness. Among the various widespread misunderstandings related to health, a very common misunderstanding is: “Everyone has to die of something”. Reality – Certainly everyone has to die of something, but death does not need to be slow, painful, or premature. Death is inevitable, but a life of protracted ill-health is not. Exercise is good ‘medicine’ is now well accepted by the health community. Adopting Holistic Health Approaches involving regular participation in physical activity, among others, provides freedom from a life of protracted ill-health, improves quality of life, and achieves healthy ageing. Its time to decide: change your future and make health last.
However, I conclude with a word of caution:
LONG you have been eating bad food and inactive for a long time, don’t expect results to come overnight; that’s not gonna happen.