Intensity Level of Endurance Exercise and its Effect on Males with Elevated Blood LDL-C Levels

Cardiovascular disease risk reduction has been associated with regular exercise. The underlying mechanism for these benefits is believed to involve low levels of low-density lipoprotein cholesterol (LDL-C). This study aimed to investigate the impact of different exercise intensities (low, medium, and high) on LDL-C levels, lipoprotein profiles, and other cardiovascular parameters in a controlled homogeneous population. The participants, comprising eighteen males aged 35 to 60, engaged in low, medium, or high-intensity endurance exercise for 45-60 minutes per day, three times per week, over a period of eight weeks. Based on their maximum heart rates, the participants were divided into three groups (low intensity: 50-65%, medium intensity: 65-75%, and high intensity: 80-90%). Statistical analysis (paired t-test) revealed that endurance training had a positive effect on reducing LDL-C levels at medium (p = 0.029) and high (p = 0.042) intensities, with statistical significance (p < 0.05). However, no statistically significant effect was observed at low intensity (p = 0.096). The Schiff test further demonstrated that medium-intensity endurance exercise was superior to other intensities in reducing LDL-C levels (mean = 201.67). Additionally, Scheffe's test indicated that moderate-intensity endurance training was superior to other intensities in the LDL/HDL ratio, while high-intensity endurance exercise was superior in increasing HDL-C levels. Furthermore, the study established a statistically significant link (p < 0.05) between endurance exercise and improvements in cardiorespiratory efficiency, as evidenced by improvement in VO₂max, resting heart rate, blood pressure, and anthropometric alterations such as body mass index and weight.