DISCUSSION
bradycardia, fatigue, epilepsy, seizure, hyperactivity, Seizure, pain, peripheral fatigue, hypotension, injuries
ADVERSE EFFECTS, HEAT, CORTEX, EPILEPSY
In our study, the effect of transcutaneous auricular VNS applied for 4 days on healthy young individuals on pain, fatigue, blood pressure, heart rate, distance covered, lactic acid level, and autonomic nervous system activity was investigated. Volunteers participating in the study were randomly divided into three groups as unilateral left stimulation, BS, and bilateral sham stimulation with equal numbers of males and females. Overall, we can argue that auricular VNS can reduce pain and fatigue and accelerate recovery by reducing exercise‐induced sympathetic hyperactivity. We can also think that BS is superior to unilateral left stimulation, as seen in the decrease in lactic acid levels. We found that the changes in blood pressure and pulse with auricular VNS paralleled the changes in autonomic activity, and that VNS (left or bilateral) did not cause bradycardia or hypotension. With all these, we saw that VNS did not increase cycling distance.Today, sport is one of the most important social activities that is followed with great interest by a wide audience and performed by most of us personally. Even in today's world countries, sports have become the way for countries to show strength to each other. As such, it is not just an athlete who is involved in physical activity. In recent years, professional athletes in all branches of sports have a very intense training and match schedule. For example, in the US National Basketball League, it is seen that athletes play every 2 days in some periods. When football clubs are considered, when the league, European, and cup matches come to the same period, the athletes play in periods of 2–3 days. As a result of this intense calendar, the recovery of the athletes cannot reach the desired level. Inadequate recovery, on the other hand, reduces performance in the long run and can lead to injuries in addition to this. Parasympathetic capacity is the determinant of restructuring and recovery (restoration) after exercise (Chen et al., Cook et al. (Studies in the literature evaluate pain perception together with heart rate, systolic, and diastolic blood pressure (Koltyn & Arbogast, In a study consisting of 18 healthy adult male geneticists, the level of fatigue was regularly questioned during cycling exercise and rest, and a numerical fatigue scale was used for this (Micklewright et al., A total of 14 healthy individuals participated in a study investigating the effect of HRV on biofeedback, autonomic function, and functional connectivity of the prefrontal cortex. Autonomic nervous system was evaluated with the Polar H10 device and the Elite HRV program (Schumann et al., The lactate scout device was used in the study evaluating the lactate concentration in the blood of 17 Polish sprinters competing in the elite 100 m category (Kawczyński et al., Uthman et al. published a 12‐year observation in their study investigating the effectiveness of VNS in patients with epilepsy. A total of 28 people with persistent epilepsy participated in the study. The VNS was performed using a device implanted in the neck. Seizure numbers were noted over the 12‐year observation period from the initial moment. The side effects of the application were found to be mild to moderate. The mean seizure frequency was found to decrease by 26% after 1 year, 30% after 5 years, and 52% after 12 years with VNS (Uthman et al., A total of 16 people participated in Koltyn et al.’s study evaluating pain perception following aerobic exercise. As an exercise, a bicycle ergometer was used for 30 min. A 30‐min rest period was applied after the exercise. In the study, pain was evaluated with a numerical pain scale and an algometer. There was an increase in pain perception after an acute exercise. However, there was a decrease in pain perception during exercise compared to the rest period (Koltyn & Arbogast, There are research studies about VNS effect on pain. Bush et al. conducted an experimental study investigating the effect of transcutaneous VNS on pain perception. It was evaluated with a quantitative sensory test including the tonic heat pain paradigm in 48 healthy volunteers. Each subject attended two experimental sessions in a random order with stimulation or sham stimulation on different days. The stimulated group significantly reduced the level of pain during continuous application of painful heat for 5 min compared to the sham group. No related changes in cardiac or respiratory activity or clinically relevant adverse effects were observed during administration (Busch et al., De Souza et al. investigated the acute effects of two types of aerobic exercise on maximum strength and endurance. Eight men with a high level of physical activity participated. It has a randomized design in which all subjects complete both control and experimental conditions. Each session was held 1 week apart. The study revealed that both aerobic and strength exercises produced significant peripheral fatigue in the same muscle group (De Souza et al., Another study was conducted investigating the effect of noninvasive VNS on fatigue and immune responses in patients with primary Sjögren's syndrome. The VNS was applied from the cervical region in a noninvasive manner, twice daily over a 26‐day period. They found that the vagus nerve may play a role in the regulation of fatigue and immune responses in patients with primary Sjögren's syndrome and may reduce the clinical symptoms of VNS related to fatigue and sleep problems (Tarnet al., 