Exercise-Induced Changes in Blood Lactate and Heart Rate Recovery Among Young Adults at the National Stadium, Lagos

Assessment of blood lactate accumulation and heart rate recovery provides valuable physiological insight into cardiovascular fitness and exercise capacity in active individuals. This study examined exercise-induced changes in blood lactate and heart rate recovery among young adults at the National Stadium, Lagos, South West Nigeria. Fifty physically active adults aged 18 to 30 years were recruited from the stadium's athletic users. Participants performed a standardised graded treadmill exercise protocol at increasing intensity until volitional exhaustion. Blood lactate was measured from fingertip capillary samples at rest, peak exercise, and at five and ten minutes of recovery using a portable lactate analyser. Heart rate recovery at one and two minutes post-exercise was calculated. Descriptive statistics and Pearson correlation were applied. Results showed a significant exponential increase in blood lactate with exercise intensity, with peak lactate occurring at maximal effort. Heart rate recovery at one minute was significantly faster in participants with lower peak lactate, indicating better cardiovascular fitness. Those who exercised more than four times per week demonstrated significantly superior lactate clearance and heart rate recovery compared to infrequent exercisers. The study concludes that exercise frequency is a key determinant of metabolic fitness in young adults in Lagos. Blood lactate and recovery heart rate are recommended as accessible fitness monitoring tools in athletic centres. Keywords: blood lactate, heart rate recovery, exercise, physical fitness, Lagos.