The season for running has arrived. However, running without proper preparation can harm your health, so caution is required. This is because you must properly understand your four “health indicators” to run in a way that suits your health condition.

“Before starting exercise, it's crucial to know your current health status and understand the appropriate level of exercise needed to maintain your health,” said Professor Hong Jun-hwa of the Endocrinology Department at Daejeon Eulji Medical Center, Eulji University. “It's advisable to begin exercising only after knowing your blood sugar, blood pressure, body mass index (BMI), and cholesterol levels.”

Why is it necessary to know your blood pressure, blood sugar, BMI, and cholesterol levels before running, then, and how should these health indicators be managed?

High blood pressure: even younger people can't remain complacent

Normal blood pressure is 120/80 mmHg. While blood pressure readings of 140/90 mmHg or higher at a hospital are typically diagnosed as hypertension, readings of 120-139 mmHg systolic or 80-89 mmHg diastolic are also considered abnormal and classified as “prehypertension.”

While hypertension was traditionally considered a disease of middle-aged and older adults, recent statistics show a steady increase in its prevalence among younger adults in their 20s to 40s. The problem is that over half of these individuals live unaware that they even have hypertension.

Unless blood pressure is measured, there are almost no noticeable symptoms, making it easy to dismiss as simple fatigue or poor condition. Another reason is that being young can make it difficult to recognize the symptoms of the disease.

“Hypertension can lead to fatal cardiovascular diseases like myocardial infarction or stroke later on. Therefore, if there is a family history, it is advisable to manage it more systematically. If you drink alcohol, smoke, or frequently eat high-calorie foods, it is good to measure your blood pressure regularly,” Professor Hong said.

Hypertension isn't the only danger. Hypotension is also a significant health risk factor. Blood pressure is considered hypotensive if the systolic pressure is below 90 mmHg or the diastolic pressure is below 60 mmHg. Unlike hypertension, its risks are less widely known, but severe hypotension can interfere with blood supply to vital organs like the brain and heart, potentially leading to fainting or organ damage.

High blood sugar increases risk of myocardial infarction and stroke

Normal fasting blood sugar (before breakfast) is below 100 mg/dL, and blood sugar two hours after a meal is below 140 mg/dL. Typically, a fasting blood sugar of 126 mg/dL or higher indicates diabetes. However, even if fasting blood sugar is between 100 and 125 mg/dL, if blood sugar rises to 200 mg/dL or higher two hours after starting a meal, this also suggests possible diabetes and requires consultation with a specialist.

However, some individuals may fall within the normal range below 100 mg/dL but are diagnosed with “prediabetes” or early-stage diabetes due to their HbA1c (glycated hemoglobin) levels. HbA1c is an indicator showing the average blood glucose level over the past two to three months. Generally, a level below 5.6 percent is considered normal, 5.7 percent to 6.4 percent indicates prediabetes, and 6.5 percent or higher is diagnosed as diabetes.

“Reports indicate that in diabetic patients with high blood sugar, lowering HbA1c by 1 percent reduces the risk of diabetes-related death by 21 percent, peripheral vascular disease by 43 percent, and the likelihood of myocardial infarction or stroke by over 10 percent,” Hong said. “To manage it, it is helpful to reduce intake of carbohydrates and fructose in your diet and consume a balanced variety of foods rich in protein and dietary fiber.”

Obesity directly impacts quality of life and longevity

The BMI (Body Mass Index) is an indicator of obesity levels. It is calculated by dividing body weight (in kilograms) by the square of height (in meters). In Korea, the standard for adult obesity is set at a BMI of 25 or higher. Obesity is categorized into three stages: stage 1 (BMI 25–29.9), stage 2 (BMI 30–34.9), and stage 3 (BMI ≥35), which is classified as severe obesity.

Simply measuring waist circumference can indicate health risks associated with obesity. Abdominal obesity is defined as a waist circumference of 90 cm or greater for men and 85 cm or greater for women. Waist circumference is measured using a tape measure around the waist, positioned halfway between the lowest point of the rib cage and the top of the pelvis, while standing with feet about 25-30 cm apart and exhaling comfortably.

“In modern society, obesity is one of the major causes of serious health problems. It is not merely an aesthetic issue but a disease that requires management because it can directly impact quality of life and even life expectancy,” Professor Hong advised. “Particularly, lifestyle changes alone are often insufficient for obesity control, so seeking active counseling and treatment is also a good approach.”

High cholesterol levels increase risk of atherosclerosis

Cholesterol is a type of lipid that forms the membranes of all cells in our bodies and is an essential substance for life. When excessive amounts circulate in the blood, it causes atherosclerosis; conversely, insufficient levels shorten the lifespan of red blood cells, making anemia more likely.

Cholesterol includes good cholesterol (HDL) and bad cholesterol (LDL). Good cholesterol helps remove harmful fat components from the bloodstream, while bad cholesterol accumulates on artery walls, increasing the risk of atherosclerosis and cardiovascular disease.

Total cholesterol, which includes good cholesterol, bad cholesterol, and triglycerides, is considered favorable when it is below 200 mg/dL. Good cholesterol is typically considered normal at around 40-60 mg/dL. For bad cholesterol, target levels vary depending on accompanying conditions. While the general target is below 130 mg/dL, patients with diabetes should aim for a level below 100 mg/dL, those with diabetes-related complications should aim for a level below 70 mg/dL, and those with cardiovascular or cerebrovascular disease should aim for a level below 55 mg/dL.

Cholesterol levels should be monitored and managed through regular check-ups.

“For most people, lifestyle changes and diet alone have limitations in controlling cholesterol. Therefore, if you are taking cholesterol-lowering medication, you should not arbitrarily stop taking it even if you feel your symptoms have improved,” Professor Hong advised.