Comparison of the effect of two intense interval training programs on salivary cortisol and testosterone in active young men

Dissertation for Master's degree (M. A )

Inclination: Exercise Physiology

is (Banfi et al., 1993, Ververn et al., 1991).

Therefore, increasing exercises, especially if their intensity and duration are high, may cause overtraining and performance drop and bring negative physical and psychological consequences. Among the biochemical indicators for evaluating the overtraining status in athletes, their hormonal profile is especially cortisol, testosterone and the ratio of testosterone to cortisol, which are evaluated to control training pressure (Hogg et al., 2003, Ververen et al., 1991). The most common practice in athletes is to check the levels of hormones cortisol, testosterone and the ratio of testosterone to cortisol, which are evaluated to control training pressure. According to the researches in the field of hormonal changes in adaptation to intense interval training, as well as a study that compares intense interval training with short and long bursts, has not been done. Therefore, the aim of this study is to compare two intense interval training programs on salivary cortisol and testosterone of active young men. Materials and methods: 30 healthy young men were randomly divided into groups of intense interval training with short intervals (10 people), intense interval training with long intervals (10 people) and traditional group (10 people). Aerobic exercise program was 3 sessions per week for 4 weeks. Cortisol and testosterone levels were measured before and after the intervention. Correlated t-test was used for intragroup analysis of variables and ANOVA test was used for intergroup comparison. Findings: The results showed that four weeks of intermittent training with short bursts and intermittent long bursts caused a significant decrease in cortisol levels and the ratio of testosterone to cortisol and an increase in testosterone levels in the experimental group. Also, the results of the research showed that after 4 weeks of intermittent training with short bursts, cortisol levels and the ratio of testosterone to cortisol were significantly lower compared to the traditional group. It was also observed that after 4 weeks of intermittent training with short and long periods, testosterone levels were higher than the traditional group.

Conclusion: The present study showed that four weeks of intense intermittent training led to a decrease in cortisol levels and the ratio of testosterone to cortisol, while it led to an increase in testosterone levels.

Key words

Intense interval training, cortisol, testosterone, active young men

Chapter 1

(research overview)

1.1. Introduction

Periodic training is one of the most common training methods to improve endurance performance. To determine the intensity of training, there is a minimum that exercises with a lower intensity with any training volume will not have a beneficial effect. Intense interval training (HIIT[1]) is one of the new methods of interval training that has attracted the attention of athletes, trainers and sports science researchers in recent years. Usually, HIIT exercises are relatively short and intermittent training sessions that are often performed with maximum effort and strength (Paul et al., 2002).

On the other hand, hormones are compounds that are produced by small glands in the body and coordinate structural and physiological changes in that area and play a role in many vital factors of the body. Cortisol hormone is the most famous glucocorticoid in the body, which is secreted by the cortex of the adrenal gland in the adrenal gland. This hormone is secreted in the body in response to inflammation and plays an important role in the body's immune system (Alumi et al., 2003). Also, testosterone, which is secreted in the testicular tissue, has anabolic effects in the body that promote muscle building (Gonz?lez Bono et al.Testosterone, which is secreted in the testicular tissue, has anabolic effects in the body that promote muscle building (Gonzalez Bono et al., 1999). The results of research on the effects of intense intermittent exercise on these two hormones are contradictory and the mechanism of the effect of this type of exercise on these two hormones has not been clearly clarified, therefore, it is necessary to conduct research in this field.

2.1. Statement of the problem

In the last decade, sports science researchers using a combination of speed training (ST) and interval training (IT) invented a new method of training called intense interval training (HIT), which improves both aerobic and anaerobic systems. Intense interval training is attributed to repetitive bouts with relatively short interval activities with an intensity close to the intensity that VO2peak is obtained (? 90% of VO2peak). Depending on the intensity of the exercise, a HIIT effort may last from a few seconds to several minutes, with the various bouts separated by a few minutes of rest or low-intensity activity (Powell et al., 2002). The distinctive feature of these exercises is their very low volume, which in a study showed a significant improvement in sports performance with only 6 training sessions during 2 weeks (Gibala and McGee, 2008).

The mechanism of these exercises is as follows: a single HIT session increases the concentration of energy substrates and the activity of enzymes related to anaerobic metabolism, while increasing the frequency of intense repetitions and performing it alternately with Recovery between activity phases changes muscle cell needs and metabolic pathways, in ways that simultaneously involve aerobic and anaerobic energy production devices in ATP regeneration. Therefore, by using these exercises, a wide range of metabolic and functional adaptations can be expected (Dawson et al., 1998). Evidence shows that if the recovery time between intense bouts is reduced, the contribution of glycolysis to provide energy is also reduced, and as a result, aerobic metabolism increases to compensate for this energy deficit. Linusier et al.[2] (1993) suggested that aerobic metabolism plays an important role during recovery periods of intense exercise for phosphocreatine regeneration and lactic acid oxidation (lactate removal). This would reveal that HIT is directed toward aerobic metabolism, which increases aerobic metabolic capacity (Leonozier et al., 1993). According to a wide range of studies on HIT, in which researchers have used bursts of 5 seconds to 4 minutes of activity as HIIT, which are divided into two categories based on the time of the bursts of activities:

HIIT with the volume of short bursts: bursts of activity less than or equal to 69 seconds that are performed with an intensity equal to the maximum or close to the maximum power or speed as intense interval training with low volume in We consider (Gibala et al., 2012). For example, we can refer to the training program of Little et al.'s (2010) research in this field: 19 repetitions of 69 seconds with 55 seconds of active recovery between each repetition (Little et al., 2010).

HIIT with high burst volume: activities with longer bursts, from 1 to 4 minutes, which are known as HIT, but with a lower intensity than HIT with volume Short bursts are performed (Gonz?lez Bono et al., 1999). For example, we can refer to the training program of Gord et al. [3] (2010) in this field: 10 repetitions of 4 minutes with 2 minutes of active recovery between each repetition (Gard et al., 2010).

Jibala et al. It is 75 kilojoules. Also, the exercises increased the buffering capacity of the muscle. They stated that despite their low volume (approximately 90% less than the endurance training group), such exercises bring similar adaptations compared to the endurance group (Gibala et al., 2006). Esfarjani and Larsen [5] (2007) investigated the effect of 10 weeks of HIT and endurance in 6 proportionally trained runners. They observed a significant improvement in VO2max (6.2%), vVO2max (7.8%), Tmax (32%) and 3000m time running (-3.4%). But the speed at the lactate threshold did not change significantly (Esfarjani and Larson, 2007).