Blood lactate and heat stress during training in rowers

Heated environment offsets the cardiovascular responses to prolonged rowing exercise in competitive athletes

Prolonged rowing exercise sessions are often prescribed considering competitive training schedules, and under hostile environments (e.g., heated ambient). The study aimed to investigate the effect of heat stress (HS) on physical performance, Lactate concentration ([Lac]), and cardiorespiratory responses during prolonged exercise sessions in competitive rowers. Twelve rowers performed preliminary exercise tests (2-km test and five-step incremental lactate test) to assess the target workload intensity corresponding to a 2.5 mmol^.L^-1 of [Lac]. On two separate days, participants were enrolled in two exercise sessions of 12 km in a rowing machine under HS (∼30 °C) and thermal comfort (TC 22 °C) conditions. Heart rate (HR), stroke volume (SV), cardiac output (CO), oxygen uptake (VO₂), [Lac], and the rating of perceptual exertion (RPE) were obtained. From baseline, HS increased the maximum temperature of the face compared to TC. Workload and VO₂ reduced while RPE increased at 9- and 12-km of rowing exercise under HS compared to TC. From baseline to the last stage of exercise, HS shifted SV downwards and HR upwards compared to TC. Consequently, CO did not change between thermal conditions (TC vs. HS). Therefore, HS provokes a cardiovascular drift during prolonged rowing in comparison to TC. The last stages of prolonged rowing sessions under HS seem to be critical to physical performance and relative perceptual of effort in rowers.

Usefulness in Developing an Optimal Training Program and Distinguishing between Performance Levels of the Athlete's Body by Using of Thermal Imaging

The goal of the training is to enable the body to perform prolonged physical effort without reducing its effectiveness while maintaining the body’s homeostasis. Homeostasis is the ability of the system to maintain, in dynamic balance, the stability of the internal environment. Equally as important as monitoring the body’s thermoregulation phenomena during exercise seems to be the evaluation of these mechanisms after physical effort, when the athlete’s body returns to physiological homeostasis. Restoring homeostasis is an important factor in body regeneration and has a significant impact on preventing overtraining. In this work we present a training protocol using a rowing ergometer, which was planned to be carried out in a short time and which involves working the majority of the athlete’s muscles, allowing a full assessment of the body’s thermal parameters after stopping exercise and during the body’s return to thermal equilibrium and homeostasis. The significant differences between normalized mean body surface temperature obtained for the cyclist before the training period and strength group as well as before and 10 min after training were obtained. Such observation seems to bring indirectly some information about the sportsperson’s efficiency due to differences in body temperature in the first 10 min of training when sweat does not play a main role in surface temperature. Nearly 1 °C drop of mean body temperature has been measured due to the period of training. It is concluded that thermovision not only allows you to monitor changes in body temperature due to sports activity, but also allows you to determine which of the athletes has a high level of body efficiency. The average maximum body temperature of such an athlete is higher (32.5 °C) than that of an athlete who has not trained regularly (30.9 °C) and whose body probably requires further training.

The physiology of rowing with perspective on training and health

PURPOSE

This review presents a perspective on the expansive literature on rowing.

METHODS

The PubMed database was searched for the most relevant literature, while some information was obtained from books.

RESULTS

Following the life span of former rowers paved the way to advocate exercise for health promotion. Rowing involves almost all muscles during the stroke and competition requires a large oxygen uptake, which is challenged by the pulmonary diffusion capacity and restriction in blood flow to the muscles. Unique training adaptations allow for simultaneous engagement of the legs in the relatively slow movement of the rowing stroke that, therefore, involves primarily slow-twitch muscle fibres. Like other sport activities, rowing is associated with adaptation not only of the heart, including both increased internal diameters and myocardial size, but also skeletal muscles with hypertrophy of especially slow-twitch muscle fibres. The high metabolic requirement of intense rowing reduces blood pH and, thereby, arterial oxygen saturation decreases as arterial oxygen tension becomes affected.

CONCLUSION

Competitive rowing challenges most systems in the body including pulmonary function and circulatory control with implication for cerebral blood flow and neuromuscular activation. Thus, the physiology of rowing is complex, but it obviously favours large individuals with arms and legs that allow the development of a long stroke. Present inquiries include the development of an appropriately large cardiac output despite the Valsalva-like manoeuvre associated with the stroke, and the remarkable ability of the brain to maintain motor control and metabolism despite marked reductions in cerebral blood flow and oxygenation.