Chapter 5: What About Physical Activity?
Lessons for South Asians at Risk for Diabetes and Heart Disease
Just like patients who receive a prescription to start taking cholesterol medication, I often write in clinic a healthy active living prescription for healthy diet and regular exercise, so patients take them as seriously as their prescription medications.
What do we mean by physical activity?
Physical activity is activity that increases one’s heart rate and breathing rate and can lead to perspiration. Activities that we do that bring this on be it housecleaning to jogging to playing soccer are referred to as physical activity. The most common form of activity is walking, brisk walking, walking with a heavy load, walking uphill, or walking up stairs and all count as physical activity. In high income countries where weight gain is a common consequence of an urban lifestyle and sedentary jobs, adults who are health conscious try to join a gym, take on a running club, or run a marathon. In other countries such as India especially in rural areas, or for those with manual labour jobs which are physically taxing - “leisure-time” exercise is not something to think about because the days’ work is so physically onerous.
Regular physical activity has been a part of a healthy mode of living for centuries as indicated in the Ayurvedic Texts. The World Health Organization (WHO) reports that over a quarter of the global adult population does not engage in sufficient physical activity in 2022 (Physical Activity, 2022). Physical activity levels are drastically different comparing rural India to urban India and urban North America. Specifically, individuals in rural areas tend to engage in higher levels of physical activity compared to those in urban areas of India. This is primarily due to the nature of occupations in rural regions, which often involve more manual labour and physical tasks. In Canada the SAHARA randomized trial along with other evaluations have generally shown South Asians in North American perform lower levels of physical activity compared to their counterparts in rural India (Anand et al., 2016; Fernando et al., 2015; Lear et al., 2017).
In parallel the minutes we used to expend being active have been replaced by minutes spent sitting usually in front of computer screens. The average office worker or person “working from home” spends 6-8 hours per day in front of a computer usually sitting. Furthermore, trying to make up for the time spent sitting by doing an aggressive “work-out” doesn’t compensate - the recommendation is to stand at your desk, and to interrupt sitting screen time with walks around your building or local neighbourhood.
A typical North American day in cities not designed for walking is reflective of the sedentary life that many of us lead – driving to work, sitting in front of a computer screen 8-hours of work, and then driving home, followed by eating, reclining, or lying on the couch, and again watching our screens on a laptop or flat-screen television in our leisure time. Recognizing the time spent sitting and time spent in front of a screen in totality is very informative - many health studies have measured both sedentary and time spent being active, exercising. There are many wide spread benefits of regular physical activity on cardio-metabolic processes (Ashcroft et al., 2024).
Here is what we know about physical activity and sedentary times effect on health. 10,000 steps per day is a commonly recommended physical activity goal that can have several health benefits.
Often, we think of and hear in the media that our fat stores are directly related to a “calories in calories out” calculation, but in the previous chapter I reviewed how the type of calories also matter when we think about health. Physical activity and sedentary behaviours are the two factors which also impact our propensity to increased body fat. For South Asians that means the Canadian Tire which appears at key times in our lives: 1) men in their early 20s when they become less active no longer doing school-based sports or university intramurals, 2) women this becomes noticeable after each successive pregnancy with weight retention typically in the order of five to 10 pounds per pregnancy, and 3) after age 50 for adults who have “gained a pound a year” – this insidious weight gain especially among women after the menopause. How then should we think about physical activity and minimizing sedentary behaviors to minimize the chance of our developing a Canadian Tire?
Just like patients who receive a prescription to start taking cholesterol medication, I often write in clinic a healthy active living prescription for healthy diet, regular exercise, and resistance training, so patients take them as seriously as their other medications.
Ideally a lifelong love of healthy active living can be inculcated in all children from a young age - this outdoor activity, organized sports, or daily yoga and fitness practice, would ideally take hold and stay with the individual long term. In South Asian culture and sub-cultures there are the added challenges of gender-based stigma around playing sports and developing visible muscles. Proactive parents should recognize that optimizing the health of their families begins with a strong recognition and endorsement of the importance of minimizing ultra processed foods and maximizing activities for families to preserve good health of parents and their children.
In high income countries like Canada, we have winter and summer sports, and we have many opportunities in school for children to play them. However, in university/college and afterwards regular physical activity must become a deliberate practice, or else it won’t find a place into our busy lives, especially with marriage and children further competing for adult’s time.
The tough part of making regular physical activity a deliberate practice is because in general our workplaces do not make regular exercise easy for us – although this is context dependent. People who live in “walkable cities or neighbourhoods” can walk for errands, walk to work, and/or walk to school. People who choose or are forced to live a long distance from work, errands, and school however have to drive or take transportation everywhere. So much of why we choose a place to live has to do with the house, its price, its space, but often less to do with our health and happiness. Perhaps with the societal reckoning on-going regarding the climate crisis, choosing where to live will land more of us right in the heart of a walkable, beautiful neighbourhood, and car ownership will decline…
Personal trainers, Health Coaches; Social Networks
Should you join a gym, should you join Weight Watchers, should you join other groups that help you to bring about lifestyle changes? It is possible, there is some evidence that social support networks in exercise and in dietary changes are effective, and thus if you have the financial means these can be effective and can include joining an exercise or weight loss group, or even joining a personal trainer. The Diabetes Prevention Project was a highly successful lifestyle intervention of; 1) individual case managers or “lifestyle coaches;” 2) frequent contact with participants; and 3) a structured, state-of-the-art, 16-session core-curriculum that taught behavioral self-management strategies for weight loss and physical activity; and 4) supervised physical activity sessions (DPP Research Group, 2002). In this randomize clinical trial the lifestyle intervention decreased the incidence of type 2 diabetes by 58% compared to usual care more so that the 31% reduction observed in the metformin-treated group!
Furthermore, resistance training is associated with lower mortality by 21% (Saeidifard et al., 2019). This type of routine may result in weight and fat loss, decrease central obesity, and lead to improvements in cardio metabolic factors (Limbachia et al., 2022).
Sleep, Naps and Rest:
The relationship between sleep and cardiometabolic health is complicated. Non-experimental research studies have shown, too little sleep, and too much sleep are both associated with increased mortality – mostly attributed to cardiovascular causes. The optimal duration of continuous sleep in a 24-hour period appears to be 8 hours – durations < 6 and > 9 are associated with adverse health consequences like diabetes. Taking naps can be good for your health, especially if you are not getting enough sleep at night. Napping can help you feel more alert and refreshed, and may have several health benefits, including improved thinking ability, immunity boost and lower stress. Short naps of 20-30 minutes are generally considered ideal, as it can provide a quick energy boost without disrupting nighttime sleep. Shift work – meaning working days and being awake during an individual’s usual sleeping hours also has adverse consequences for health. The metabolic pathways which are disrupted affect appetite, signals to the brain, and have been shown to increase blood pressure, cholesterol, body weight, and blood glucose. Shift work has been found to have a negative effect on cholesterol levels. Several studies have shown that working irregular or night shifts is associated with an increased risk of dyslipidemia, which is a condition characterized by abnormal levels of cholesterol and/or triglycerides in the blood. One study published in the journal "Atherosclerosis" in 2016 found that shift workers had higher levels of LDL ("bad") cholesterol and lower levels of HDL ("good") cholesterol compared to non-shift workers. Another study published in "PLOS ONE" in 2015 found that shift work was associated with an increased risk of metabolic syndrome, a cluster of conditions that includes dyslipidemia as a key component (Guo et al., 2015). Naps (think siestas in Spain, afternoon naps in Greece) in some cultures are considered a normal part of the daily routine. Short duration naps e.g., 20 minutes that are sometimes labelled “power naps” can be beneficial whereas naps beyond that duration can make it difficult for an individual to return to normal pace due to a “hang-over” effect and may disrupt night-time sleep.
What I recommend as the Optimal Activity Prescription for Health:
Randomized trials or interventions where physical activity was independently evaluated for its impact on body weight, body adiposity, and other risk factors have collectively shown that regular physical activity is associated with improved cardio-metabolic health (Armstrong et al., 2022; Battista et al., 2021). RCTs to reduce sedentary time have shown that interventions introduced in early childhood result in significant decreases in behavior compared to interventions given to adults, suggesting that instilling healthy habits early in life is important (Downing et al., 2018; Shrestha et al., 2019; van Grieken et al., 2012). A systematic review of South Asian specific trials that we conducted showed that regular physical activity was associated with improvements in CVD risk factors, including blood pressure and cholesterol levels– and thus findings are generally consistent with the larger studies conducted in allcomers (Limbachia et al., 2022).
The Diabetes Prevention Project nicely showed addition of a personal trainer to once daily routine as a way to re-enforce and motivate an individual to keep exercising is effective, as did an RCT from Israel showing both low carbohydrate diet and regular physical activity regularly contribute to weight and fat loss, with the change to a low carb diet having the greater impact than the physical activity, but both contributed independently to weight and fat loss (DPP Research Group, 2002; Gepner et al., 2018).
Strength training:
Finally, a note on strength training. Increased muscle mass improves strength, prevents injury, and can improve weight maintenance and certain cardiometabolic processes such as improved glucose control. Muscle mass begins to decline after the age of 50 years so the peak years to build strength are before this. The adage “use it or lose it” applies here too. Modest strength training including push-ups, power yoga, light weights are easy to do with minimal expense. Of course, more elaborate programs are beneficial too albeit sometimes more costly. The greatest barrier to strength training programs is motivation of individuals to maintain them overtime. Social engagement with friends or coworkers around fitness is a good way to maintain exercise programs and keep it enjoyable.
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