Background and objectives: It is possible for the body’s function not to be the same during or after exercise activities in different parts of the day. Consequently, the objective of the present study is to evaluate the impact of the time of physical activity (morning or evening) on the amount of myoglobin and creatine kinase in non-athletic men with cardiovascular diseases.

Method: fifteen men with cardiovascular diseases were chosen as the test cases of the study. On the day of the test, the test cases gave a pre-test blood test at 7 o’clock in the morning and then carried out the exercise protocol under the supervision of a specialist. They gave blood tests immediately after and three hours after the exercise protocol. The test cases went through exactly the same process a week later but this time at 7 o’clock in the evening. Data analysis was conducted via SPSS. 20.

Results: the present study revealed that there was no considerable difference in the amount of myoglobin before the morning test and immediately after the morning test (P= 0.299) and before the morning test and 3 hours after the morning test (P= 0.877). Likewise, before the evening test and immediately after the evening test (P= 0.908) and before the evening test and 3 hours after the evening test,(P= 0.487) the amount of myoglobin did not differ considerably. In addition, there was no considerable difference in the amount of creatinekinase before the morning test and immediately after the morning test (P= 0.536) and before the morning test and 3 hours after the morning test (P= 0.930). Similarly, before the evening test and immediately after the evening test (P= 0.822) and before the evening test and 3 hours after the evening test,(P= 0.952) the amount of creatine kinase did not differ considerably. Moreover, in the immediate pre-test, post-test averages, and 3 hours after the tests in both morning and evening tests of both indexes, there was no significant difference.

Conclusion: day-and-night rhythm and cycle has probably no impact on the response of myocardia tissues and skeletal muscles.