The outcomes of the current study showed that long-term (16 weeks), regular (2 hrs, three times per week) of participation in swimming sessions effect positively on chronic metabolic disorders including T2DM, hyperlipidemia, and HTN in men and women aged 52.4±5.5 yrs. The results revealed that there were statistically significant differences at p ≤ 0.05 between pre- and post- tests of (TC, HDL, LDL, TG, glycemic parameters, systolic blood pressure, diastolic blood pressure, BMI and fat percent) in the experimental group for both genders. As the Δ % for men were (-22.10%, 21.38%, -30.48%, -23.03%, -37.46%, -17.21%, -12.04%, -8.15%, -17.99%), respectively. In addition, the Δ % for women were (-24.47%, 21.77%, -35.37%, -22.65%, -25%, -13.15%, -9.92%, -11.55%, -18.99%), respectively.
Whereas, no significant differences were found at p ≤ 0.05 between pre- and post- tests for all studied variables in the reference group for both genders. Remarkably, these results emphasize that practicing regularly swimming patients have significant and positive effects on hyperlipidemia, T2DM, and HTN in comparison with who never participates in swimming sessions.
Vanhees et al. stated that engaging in regular physical exercise and exercise interventions including swimming, cycling, jogging, and walking, which, when carried out at moderate intensity are essential components for reducing the severity of cardiovascular risk factors, such as metabolic risk factors, systemic inflammation, high blood pressure, abdominal fat, and obesity (31). However, an investigation established by Prugger et al. showed that the lower frequency of regular exercise and decreased likelihood of exercise intention were observed in coronary heart disease patients with severe depression, while the symptoms of anxiety did not affect the regular exercise intention (32).
In a study conducted by Asa et al., 20 patients with both congestive heart failure and T2DM (age 67.4±7.1) were allocated randomly to either aquatic exercise or a control group. The patients exercised for 45 min 3 times per week in 33–34◦C swimming pool temperature for 8 weeks. Hba1c decreased significantly (p ≤ 0.01) during training, while fasting glucose, insulin, c-peptide, and lipids were unchanged (26). In our opinion, Asa et al. study did not reflect the effect of swimming sessions on metabolic risk factors as in our study, as well as the mean age of the current study is different, also our conducted study was carried out for a 120 min each swimming session, 3 times weekly for 16 weeks. These factors positively affect the lipid and sugar metabolic markers’ in our study in which decreased TC, LDL, TG, glucose levels significantly in swimming session men and women groups and increased the HDL levels. This finding is in agreement with the results of a study conducted by Kasprzak et al. on 32 obese women aged 41-72 yrs for three months and showed that all mean anthropometric variables were significantly lower (p ≤ 0.01). The blood lipid profile, total cholesterol, and LDL-cholesterol were significantly lower (p ≤ 0.01). Furthermore, the levels of fasting TG, glucose, and insulin were decreased significantly (p ≤ 0.05) after finishing this study (28).
Moreover, in the current study, body mass index and body fat percent in the swimming session men group decreased significantly with Δ % of 8.15 and 17.99, respectively. While in women group decreased with the Δ % of 11.55 and 18.99, respectively. However, there were no significant changes in any of these variables in the current study reference group both genders.
However, the study by Gappmaier et al. on 38 middle-aged obese women (25-47% body fat) participated in a 13 weeks program aimed to compare the effects of aerobic water exercise vs walking on land and their results revealed also a significant reduction in body fat percent (3.7%), body weight (5.9 kg), skinfold and girth measurements, occurred in all groups. There were no significant differences between all the investigated groups as long as similar intensity, duration, and frequency are used (27).
The current study results revealed that the systolic blood pressure of the men patients in the experimental group fell significantly (p ≤ 0.05) from 151±10.61 to 125±8.36 mmHg, while the diastolic blood pressure changed significantly (p ≤ 0.05) from 99.60±4.81 to 87.60± 5.64 mmHg. There was a little change in any of these variables in the reference men group (Δ %=0.57) and (Δ %=2.14), respectively. Moreover, in the women experimental group, the results showed that systolic blood pressure fell significantly (p ≤ 0.05) from 164.90±10.64 to 143.20± 11.73 mmHg (Δ %=13.15), while the diastolic blood pressure changes significantly (p ≤ 0.05) from 97.70±2.66 to 87.50±4.32 mmHg (Δ %=9.92). There was a little change in any of the systolic and diastolic blood pressure variables in the reference women group (Δ %=4.11) and (Δ %=1.59), respectively.
Hirofumi et al. conducted a study on eighteen patients with HTN from both genders [aged 48±2 yrs) for 10 weeks using a swimming training program and the outcomes from this study showed that the systolic blood pressure of patients fell significantly (p ≤ 0.05) from 150±5 to 144±4 mmHg, while the diastolic blood pressure did not change significantly. There were no significant changes in any of these variables in the control group (33).
Predominantly, recreational swimming exercise is based on aerobic metabolism because both lipids and carbohydrates are involved as the major sources of energy. For that, aerobic exercises have a positive effect on the metabolism of these substances (28). Besides, several published studies demonstrated the positive relationship between aerobic aquatic exercise and good physiological and psychological conditions. These studies showed that regular physical exercises can reduce musculoskeletal disorders, many chronic diseases, anxiety, insomnia, depression, stress, and many others (18, 34-36).
In the post-tests (post-interventions), the findings revealed that the experimental groups for both genders were better than reference groups, and significant differences were found at (p ≤ 0.05(. These findings indicated the importance of regularly following physical exercises and practicing swimming or any physical activity to positively prevent or treat hyperlipidemia, T2DM, and HTN.
In a previous study conducted on 159 overweight men and women with mild-to-moderate dyslipidemia (aged 40- 65 yrs), Kraus et al. demonstrated that there was a beneficial effect of exercise on the variation of lipoprotein and lipid variables and the experimental groups had remarkable and positive improvements in lipids and lipoproteins in comparison with the control group (37).
In another study, Nualnim et al. sought to determine the effect of swimming training on decreasing blood pressure and improving vascular function in men and women (60±2) yrs old. The subjects were assigned to swimming exercises (experimental group) and relaxation exercises (attention or control group) for 12 weeks of a swimming training program. The results revealed a significant decrease in systolic blood pressure (SBP) in the swimming group. Swimming produced a 21% increase in carotid artery compliance. No significant changes were observed in the control group (38).
In the current study, the concentration of glucose in blood decreased significantly (p < 0.05) in the experimental groups and better than the control groups. These results emphasize that regular swimming contributes to increase the uptake of glucose into skeletal muscle and could activate some hormones like adiponectin. Punthakee et al. confirmed that the higher circulating of adiponectin is beneficial during exercise and favors the oxidation of fat and glucose uptake into muscles. In addition, the weight loss, the decrease in the percentage of fat, and blood pressure could be key elements of decreasing T2DM (39). Colberge et al. mentioned that exercise or physical activity plays a central role in the prevention and control of insulin resistance, T2DM, and diabetes-related health complications. Aerobic and resistance training improves the action of insulin and contributes to managing BP, lipids, fat, and body weight. Interestingly, T2DM patients must regularly follow different trainings and exercises to have optimal health benefits (40).
However, to the best of the author’s knowledge, no previous data documented the effect of regular long-term swimming program on patients with chronic diseases like T2DM and HTN from the West Bank/Palestine.
Similar to many other aerobic exercise studies on patients, our study was performed in a limited number of participants. A marked difficulty was to recruit patients that were free from other complicating disorders and disabling conditions like the patients who have a history of chronic pulmonary diseases, stroke, peripheral artery diseases, and nephropathy. Moreover, the patients who have severe infections, peripheral ulcers, or have problems with glycemic control, which are more common in patients with the combination of T2DM and HTN, were excluded from the current study. Furthermore, the current study was planned to be carried out for four, eight, and twelve months. Unfortunately, due to the COVID-19 pandemic, which started in our country in May 2020, we stopped the current study to protect the participants and researchers from this lethal infectious disease. A future study required to test all the metabolic risk factor markers, maximal oxygen uptake (VO2), and heart rate monitoring parameters for a longer period with a larger sample size