Patients with coronary artery disease benefit from exercise also in cold temperatures

The study evaluated for the first time the joint effect of a cold environment and exercise on aortic blood pressure after exercise among patients with coronary artery disease. Aortic blood pressure reflects the strain on the heart and the potentially associated health hazards. The effects of upper body exercise in a cold environment on the recovery of blood pressure have not been studied before. Another new aspect was studying dynamic and static exercise separately.

The study showed that the systolic pressure in the aorta decreases by 6–10 mmHg following a brisk walk, both in a cold and warm environment. Dynamic manual work also reduced systolic blood pressure by 2–4 mmHg. By contrast, static work requiring upper body muscle tension and compressive force increased systolic blood pressure by an average of 7 mmHg after exercising in a cold but not in a warm environment.

In static exercise, the muscle may be tensed for an extended period of time without any external movement, whereas dynamic work causes movement, which makes the muscle alternately contract and relax during the performance. Clearing heavy snow, for example, may involve static work, while walking and skiing are mostly dynamic exercise.

Oulu-based males aged 40–70 years with coronary artery disease who had suffered a myocardial infarction participated in the laboratory study. 11 of them walked briskly on the treadmill and rested at –15°C and at +22°C. In the second experiment, 15 subjects pedalled an arm ergometer and performed static upper body pushes forward and rested at –15°C and at +22°C. Measurements during the exercise and the rest period lasted for 30 minutes and were carried out in random order for all subjects. Their aortic blood pressure and artery stiffness were measured from the radial artery before and 25 minutes after exercise.

Following just a single occasion of exercise, blood pressure may fall for several hours or even a day, which is good for your health. Regular exercise lowers blood pressure permanently and supports the treatment of high blood pressure in patients with coronary artery disease. Cold temperature, on the other hand, is known to increase blood pressure and add to the workload of the heart during exercise, and therefore it has been thought to suppress the drop of blood pressure after exercise.

However, the study now published showed that the recovery from exercise was similar regardless of the surrounding temperature. The only exception was static exercise in a cold environment, as this was shown to increase blood pressure. The reasons for this are not yet known.

Cardiac symptoms caused by freezing temperatures, including chest pain and cardiac arrhythmia, are more common among patients with coronary artery disease, and many of them may therefore avoid exercising in the cold. However, regular exercise is important both in treating the disease and in slowing its progression. The results now published encourage people with coronary artery disease to exercise safely all year round, also during the winter.

The study was led by the Center for Environmental and Respiratory Health Research of the University of Oulu and was funded by the Ministry of Education and Culture, the Yrjö Jahnsson Foundation and the Juho Vainio Foundation.

The results of the study were published in the Scientific Reports publication series:

Heidi E. Hintsala, Rasmus I. P. Valtonen, Antti Kiviniemi, Craig Crandall, Juha Perkiömäki, Arto Hautala, Matti Mäntysaari, Markku Alén, Niilo Ryti, Jouni J. K. Jaakkola & Tiina M. Ikäheimo. Central aortic hemodynamics following acute lower and upper-body exercise in a cold environment among patients with coronary artery disease. Sci Rep 11, 2550 (2021). https://doi.org/10.1038/s41598-021-82155-x