When is a healthy BMI not good enough?

For decades, Body Mass Index (BMI) has been the oft-spoken about predictor of health within the medical community in both the positive and negative camps. Whilst it remains a guideline to a healthy weight based on the height of a person, BMI falls short in certain crucial parameters, such as its ability to distinguish between muscle and fat, as well as where the fat is located. However, BMI is not without its value. It is still used globally as an important indicator of overall health as the interpretations of it can be similar to other measures, it is virtually free, and is based on a simple calculation.

While it has been generally accepted that a person with a BMI reading of 18.5 to 24.9 is considered “healthy”, lifestyle factors such as activity levels are a determinate factor that has long been overlooked. A sedentary lifestyle and prolonged hours of physical inactivity supersede a person’s ideal body weight and BMI. This poses a particularly alarming health threat, especially in the United States of America, where the American Heart Association has reported an 83% increase in sedentary jobs since 1950. Conversely, jobs that require physical activity have dropped to less than 20% of the total U.S. workforce, translating to an approximate 50% decrease since 1960. What do all these figures mean in actuality? There is a general upward trend over the last 50 years that favors a larger proportion of time spent being inactive rather than time spent being active within the course of the day.

For the time-poor population that predominates today, a gym subscription usually lies untouched as bustling lifestyles outpace the need for exercise. Due to tight time schedules or even affordability, people don’t make it to the gym. However, doctors generally advocate that even daily light activity such as a 30-minute walk does have its benefits if done consistently over a period of time. Conscious decisions such as leaving earlier in the morning to walk 10 blocks rather than take the bus, or to do 50 squats by your desk during lunch time, all play their part in contributing to a healthier body. Good body weight and BMI should not instill a false sense of confidence in people as exercise is still an important component of a healthy lifestyle. Improved muscle tone, (including smooth muscles surrounding the blood vessels), aerobic conditioning of the heart (training the heart to pump blood more efficiently to the rest of the body), and improved lung capacity (as a direct result of increased oxygen capacity through exercise) are just some of the key benefits that can be expected from targeted and consistent exercise.

A recent 2018 study published by The American Journal of Cardiology sought to compare if healthy weight adults with sedentary lifestyles had an increased risk of developing cardiovascular disease (CVD) to individuals who are overweight. The investigators analyzed data from the National Health and Nutrition Examination Survey. Participants aged 40 to 79 who did not have a previous diagnosis of coronary heart disease, stroke, or heart attack were the primary focus of the study. After examining study parameters such as abdominal fat, waist circumference, level of physical activity and sedentary periods, as well as whether or not the participants experienced shortness of breath when walking or running up a hill, the results were clear. The findings of the study suggested that in individuals with a BMI of 18.5 to 24.9, a sedentary lifestyle increases the likelihood of being at high risk for CVD when compared to that of overweight individuals.

Fitness buffs can be guilty of a sedentary lifestyle without realizing it: intense exercise followed by a plateau of 10 hours of sitting has been shown to significantly lessen the effects of exercise on the body. How might this be possible? A simple look at an average fitness-driven, office-based individual’s typical day may help to shed some light. After starting out the day with an intense 2-hour workout, he/she commutes to work, sitting for 1-2 hours during the journey. Once at work, the regular 8-10 hour workday dictates most time is spent at a desk. The commute home takes another 1-2 hours of sitting. Once home, probably an hour is spent on the couch post-dinner and -chores before hitting the hay for the night. In a total of 16-18 waking hours, this individual has spent approximately 12 hours sitting down. If this is your typical work day and you pride yourself on being committed to your fitness, minor changes to your routine such as a walk around the office a couple of times an hour, or light exercises while Netflix is on at the end of the day, can help offset the negative effects of your sitting hours. Johns Hopkins cardiologist Erin Michos said it succinctly, “Even if you’re doing 30 minutes per day of physical activity, it matters what you do the other 23 hours of the day.”

The promotion of physical activity and cardiorespiratory fitness is crucial, especially in the US, as the burden of cardiometabolic diseases remains high. According to Dr. Mark Berman of Better Therapeutics, 70 – 90% of cardiometabolic conditions (an interrelated set of conditions that include cardiovascular diseases, such as coronary heart disease (CHD), stroke, and hypertension, as well as metabolic diseases, such as type 2 diabetes, obesity, and non-alcoholic fatty liver disease) are directly attributed to modifiable behaviors, like poor diet, sedentary activity, smoking, and excess alcohol intake. As of 2019, one out of every two American adults is living with one or more cardiometabolic diseases. Behavioral changes are what is needed, but hard to initiate and sustain.
Patient awareness and responsibility towards their own health is an important step forward in addressing this issue. One such method that can be employed is the use of fitness trackers.

Fitness trackers not only earn their place in this particular landscape by sensing and recording vital statistics, but they provide clinicians with useful insight into a patient’s body even at times when the patients aren’t with their doctor. A robust and effective treatment regime is dependent on the data that fitness trackers can provide. A cohesive platform that provides the clinicians with the patients’ data at their fingertips is not only the new incoming wave of healthcare technology advancement, but will become a core diagnostic and treatment tool in the future.

More importantly, health trackers assign patients a sense of responsibility in managing their own health by making them constantly aware of their vitals and how they fluctuate based on varying activities and times during the day. By enabling the patient to take a more hands-on role in their health, along with their physician, long-term management of their condition and a more specific therapeutic approach can be employed.