Aquatic Exercise: Effort Intensity in Diverse Environments

Researchers knew that effort intensity is a major factor in setting up an exercise program, and while studies have been conducted on land environment, such as running, field sports, etc. there are different results in aquatic environments. Fabiane Graef and Luiz Kruel wrote a review article compiled from various studies about how effort intensity differs between normal exercises and ones that take place in water. The authors made no hypothesis, yet they reviewed different works to support their study. The amount of participants in the studies is unknown, as the groups differ along with the number of studies the authors reviewed for the aquatic exercise article.

Effort intensity is mostly determined by heart rate and subjective perception of effort, yet heart rate is the easiest to measure. In most studies, the researchers recorded changes in heart rate from exercises on land versus aquatic, and it became evident that heart rate decreases when doing exercises in water, such as swimming or running in shallow water. When the human body is free, floating and less affected by gravity, more blood is pumped and the systolic volume of the heart increases, therefore reducing heart rate. In water gymnastics, it is decreased even more because more muscles are at work in the water than on land, like when both arms and legs are used to swim, and more blood needs to be pumped to those muscles. The heart rate lowers even if a person is relaxing in the water, and there is a great amount of difference in beats per minute from relaxing in water to aquatic gymnastics. It was also found that heart rate decreases more for men than women. There were some aquatic exercises, like water cycling, that were less effective in reducing people’s heart rate dynamically.

Limitations for the study of aquatic exercises included whether the heart rate would be altered by how deep the person would be in the water, and the water’s temperature. According to the review of studies, decreased heart rate can be caused by deeper immersion in water, and by lower, colder temperatures. When the human body is within or submerged in water, hydrostatic pressure causes blood to make a venous return to the heart, thereby increasing systolic volume and decreasing the rate of beats per minute. In lower aquatic temperatures, the blood also rushes to the heart to maintain body heat, and also causes an increase in the amount of blood pumped through the heart.

As for subjective perception of effort, the Borg’s Rate of Perceived Effort Scale is a useful tool to indicate an individual’s workout intensity. The results of the scale, however, may be hindered by differentiated patterns of repetitive motor gestures, and the exercise’s duration.

The authors basically came to understand that heart rate decreased in the water, influenced by pressure and body heat, and that the rate can also be affected by immersion, temperature and body position. Subjective perceptions of effort can be used to measure effort intensity with the Borg scale, however heart rate may be more reliable.

The author’s review of aquatic exercise studies supports that exercising in water environments may be healthier than normal workout conditions. The occupation of numerous muscles and a lower heart rate results in more blood being pumped, which signifies more oxygen intake, without fatigue. Aquatic exercises can result in more efficient fat loss because the body can work harder without tiring early, unlike exercises on land.