The Faculty of Humanities’ (FH) Assistant Professor of Sports Science, Dr. Zaher El Hage, at Notre Dame University-Louaize (NDU) presented his findings of aerobic health in a 20-year-old individual titled, “Overview of the Different Types of Exercise and its Effects on the Heart,” at a recent symposium. El Hage’s presentation and results are underlined by the latest scientific literature regarding heart health and exercise, how exercise differs based on intensity, and long-term bodily adaptations to aerobic training.
El Hage started off with the recommendations placed by organizations such as the American College of Sports Medicine (ACSM) and Center for Disease Control (CDC) for exercise, a general standard of 150 minutes of moderate-intensity aerobic exercise per week, and twice-weekly strength training of all major muscle groups. In comparison, the World Health Organization (WHO) breaks down its guidelines by age. Adults should aim for either 75 minutes of high-intensity or 150 minutes of moderate-intensity exercise, the latter being more suitable for older adults. Children should aim for 60 minutes of daily movement, and older adults with poor mobility are recommended to perform physical activity at least three times per week to enhance balance and prevent falls. Regarding strength training, all ages benefit from exercising major muscle groups at least twice a week, starting small and slowly increasing intensity as they progress.
What distinguishes the intensity of aerobic activity is the pace and time allotted to each type of exercise. Steady state exercise (SSE) warrants a steady flow of each session, examples of which include running, cycling, or swimming at a moderate pace. It is typically performed for 30 to 60 minutes, explained El Hage, its intensity working 60% to 85% of one’s maximum heart rate (MHR). In contrast, interval training, often in the form of high intensity interval training (HIIT), specifies its intensity in time slots that cover a maximum total of 22 minutes. A HIIT session has a work-to-rest ratio of 1:1, the work interval involving high intensity movement, followed by rest. Intervals are repeated for a certain number of sets until the individual hits the 22-minute mark, rest included.
Through a consistent exercise routine, bodily adaptations occur in the circulatory system, one of the first being improved coronary artery functioning; also connected to enhanced heart function are blood circulation, increased blood volume in terms of hemoglobin and plasma levels, increased capillary density, and decreased blood pressure. El Hage outlined the heart rate (HR), stroke volume (SV), and cardiac output (Q) of a 20-year-old at three levels of fitness: no training, moderate training, and high training. Both the MHR and resting heart rate (RHR) were inversely correlated with higher levels of training, in that high training decreases the heart beats per minute (BPM) compared to no training, from 80 to 40 BPM at rest, and 200 BMP to 180 BPM at the MHR. However, the SV and Q were positively correlated with regular exercise, the SV increasing from 80ml with no training to 220ml with high training at the MHR, and Q from 16L to 40L under the same criteria.
Other positive effects include changed bodily composition, e.g., higher muscle mass and reduced fat, as well as cellular respiration and insulin sensitivity, a protective factor against Type 2 Diabetes. El Hage cited several studies that observed the impact of aerobic exercise over a designated period of time, with one study showing the most promising results, a combination of HIIT and SSE decreasing the body’s subcutaneous fat by 18% and increasing insulin sensitivity by 46%.
El Hage concluded with a simple message: even one exercise session has immediate positive effects on cardiovascular health and mitigates heart disease. There is a wide range of exercise that is suited or can otherwise be modified to individuals of various fitness levels and abilities. Starting small is recommended, and one should not be afraid to increase the intensity, duration, and frequency of an exercise routine once progress becomes apparent. El Hage keeps exercise realistic, too: the most predictive factor for consistency in a routine is to choose a form of exercise that you enjoy. Make it fun, and both your health and mood will get a great boost.