How the National Service Builds Heart Health

National Service (NS) is an essential rite of passage for every Singaporean son; it is a defining experience and often the first time a young man undergoes rigorous physical training.

What Physiological Changes Happen During NS?

NS is a time of intense physical training and activity. During this time, the body naturally adapts, and in a positive way. Beyond earning a nice tan, full-time national servicemen (NSFs) find their body changing in various ways. They may have visible increased muscle mass, accompanied with elevated muscle strength and endurance. Many finally get the six-pack abs that they have always wanted.

In response to intense training, the respiratory system sees an increase in oxygenation and efficiency in gaseous exchange. The heart’s ability to pump blood out of the heart improves because of the increased heart chamber size that allows more blood to fill the heart. The heart’s muscle strength1 also increases. Thus, most NSFs will observe a slower resting heart rate, reflective of their increased fitness levels.

Body fat reduction also occurs. Overweight individuals could experience significant weight loss, and those with borderline hypertension may experience regulation of blood pressure as blood pressure drops slightly with weight loss.

How does NS Improve Health?

NS plays an indispensable role in improving heart health through structured training programme and emphasis on fitness in the following ways:

• Cardiovascular fitness
  Regular exercise during NS promotes cardiovascular fitness, which is robustly associated with up to 50-70% reduction of cardiovascular ailment and all cause mortality2,3.
• Weight management
  Some will attest to knowing a friend who transformed from an overweight teen to a sturdy, muscular fitness enthusiast during NS. Maintenance of a healthy weight (BMI 18.5-22.9 in Asians) is crucial to heart health. Obese individuals, compared to non-obese individuals, are at 1.5 times the risk of cardiovascular events4. Weight control plays an essential role in the prevention of diseases such as coronary artery disease, diabetes, hypertension, stroke, high cholesterol, fatty liver, sleep apnea, arthritis and depression5.
• Habit of exercise
  For many, the routine of regular exercise during NS becomes a habit that persists after NS. Regular physical activity not only prevents illness, but also promotes improved mental health and overall quality of life.

Pre-enlistment Screening for Cardiac Conditions

All NSF undergo a pre-enlistment screening at the Medical Classification Centre. This is to determine what activities a NSF could engage in. They should declare any pre-existing medical condition and undergo a very thorough eye, hearing and physical examination together with a 12-lead electrocardiogram. Further referrals to specialists may then take place.

There is an essential focus on the identification of pre-existing cardiac conditions; in fact, a significant number of pre-enlistees have cardiac conditions diagnosed through this process. NSFs with medical conditions are graded and classified in accordance with their medical conditions; consequently it could mean a potential reduction in the degree of physical activity during NS. The aim is to reduce risks, especially cardiac risks, that a NSF is exposed to during the course of his service.

Cardiac screening identifies NSFs with conditions such as hypertrophic cardiomyopathy (unusually thick heart muscle), long qt syndrome (prolonged electrical instability of the heart), Brugada syndrome (association with risk of sudden cardiac arrest), abnormal heart rhythms and any other heart ailment.

Every young man has a different experience in NS. It may seem intimidating at first and may not always be a pleasant experience, but many do look back with fondly on the camaraderie and experiences during their time of service. NSFs not only enjoy the benefits of building a sense of responsibility, mettle and team spirit, but also harvest many health benefits from the physical conditioning during NS; they lessen the disease burden and the risk of mortality.

The key is to turn those NS workouts into lifelong habits for lasting fitness and heart health.

Enlisting? Get tips to prepare for NS.

Article contributed by Dr Paul Lim, cardiologist and electrophysiologist at Mount Elizabeth Hospital and Parkway East Hospital, Singapore. Prior to his private practice, Dr Paul Lim was a Senior Consultant Cardiologist involved in the arrhythmia service at the SAF Cardiac Fitness Centre National Heart Centre Singapore.

References

1. 1. Hellsten Y, Nyberg M. Cardiovascular Adaptations to Exercise Training. Compr Physiol. 2015 Dec 15;6(1):1-32.
2. Elmaleh-Sachs A, Schwartz JL, Bramante CT, Nicklas JM, Gudzune KA, Jay M. Obesity Management in Adults: A Review. JAMA. 2023 Nov 28;330(20):2000-2015.
3. Elagizi A, Kachur S, Carbone S, Lavie CJ, Blair SN. A Review of Obesity, Physical Activity, and Cardiovascular Disease. Curr Obes Rep. 2020 Dec;9(4):571-581.
4. Wei M, Kampert JB, Barlow CE, Nichaman MZ, Gibbons LW, Paffenbarger Jr, RS, et al. (1999) Relationship between low cardiorespiratory fitness and mortality in normal-weight, overweight, and obese men. JAMA 282: 1547–1553.
5. Blair SN, Kohl III HW, Barlow CE, Paffenbarger Jr RS, Gibbons LW and Macera CA (1995) Changes in physical fitness and all-cause mortality. A prospective study of healthy and unhealthy men. JAMA 273: 1093–1098.