Effect of exercise on cardiometabolic health of adults with overweight or obesity: Focus on blood pressure, insulin resistance, and intrahepatic fat—A systematic review and meta‐analysis

Summary This systematic review examined the impact of exercise intervention programs on selected cardiometabolic health indicators in adults with overweight or obesity. Three electronic databases were explored for randomized controlled trials (RCTs) that included adults with overweight or obesity and provided exercise‐training interventions. Effects on blood pressure, insulin resistance (homeostasis model of insulin resistance, HOMA‐IR), and magnetic resonance measures of intrahepatic fat in exercise versus control groups were analyzed using random effects meta‐analyses. Fifty‐four articles matched inclusion criteria. Exercise training reduced systolic and diastolic blood pressure (mean difference, MD = −2.95 mmHg [95% CI −4.22, −1.68], p < 0.00001, I 2 = 63% and MD = −1.93 mmHg [95% CI −2.73, −1.13], p < 0.00001, I 2 = 54%, 60 and 58 study arms, respectively). Systolic and diastolic blood pressure decreased also when considering only subjects with hypertension. Exercise training significantly decreased HOMA‐IR (standardized mean difference, SMD = −0.34 [−0.49, −0.18], p < 0.0001, I 2 = 48%, 37 study arms), with higher effect size in subgroup of patients with type 2 diabetes (SMD = −0.50 [95% CI: −0.83, −0.17], p = 0.003, I 2 = 39%). Intrahepatic fat decreased significantly after exercise interventions (SMD = −0.59 [95% CI: −0.78, −0.41], p < 0.00001, I 2 = 0%), with a larger effect size after high‐intensity interval training. In conclusion, exercise training is effective in improving cardiometabolic health in adults with overweight or obesity also when living with comorbitidies.

Type 2 diabetes Type 2 diabetes mellitus NIDDM noninsulin-dependent diabetes insulin resistance hyperglycemia glucose intolerance hypertension high blood pressure fatty liver disease non-alcoholic fatty liver disease non-alcoholic steatohepatitis NAFLD NASH Figure S1. Effect of exercise training vs. control on systolic blood pressure in adults with overweight or obesity.   a. Systolic blood pressure; b. Diastolic blood pressure; c. HOMA-IR; d. Intrahepatic fat. Table S2. Summary of quality assessment of original studies.
-Systolic blood pressure -Diastolic blood pressure -HOMA-IR Short term: Comorbidities: none. RM for 3 sets. A rest of 15 to 30 sec between sets was provided. In both groups, flexibility exercises were performed before and after each exercise session. Exercise -Program duration: 16 weeks -Number of sessions: 2/week -Type of training: dynamic resistance exercise for 45-60 min per session (2 exercises for the leg extensor muscles, 1 exercise for the arm extensor muscle and 4-5 exercises for the main muscle groups of the body). During the first 8 weeks: loads of 50-70% of the individual 1-RM, and during the last 8 weeks 70-80% of the maximum. In addition, from week 8 to week 16 the subjects performed a part (20%) of the leg extensor and bench press sets with loads ranging from 30 to 50% of the maximum. -Supervised: fully.

Diet
-No exercise -Caloric restriction of 500 kcal/day During the 16 weeks of the study the subjects maintained their customary recreational physical activities (e.g. walking). Exercise -Program duration: 24 weeks -Number of sessions: 5/week -Type of training: Moderate-intensity physical activity, similar in intensity to brisk walking, was prescribed and progressed to 60 minutes. Were provided with a pedometer and step goals of more than 10 000 steps per day. diet that result in a sustained 8%to10% weight loss in 12 months. Energy intake was reduced to1200 to2100kcal/d based on initial body weight. -Supervised: partially.
diet that result in a sustained 8%to10% weight loss in 12months. Energy intake was reduced to1200 to2100kcal/d based on initial body weight. High volume MICT -Program duration: 16 weeks -Number of sessions: 2/week -Type of training: 5-10-minute warm-up and a 10-minute cool-down.Aerobic exercises, i.e. one day of the week on the treadmill, and the second one on the bike. The highvolume MICT group performed 45 minutes aerobic exercise at 65% of VO2peak. -A hypocaloric and controlled sodium diet (3-6 g/day) was prescribed for each participant. -Supervised: fully.
High volume HIIT -Program duration: 24 weeks -Number of sessions: 5/week -Type of training: 5-10-minute warm-up and a 10-minute cool-down. One day on the treadmill (4x4 minutes at 90% of VO2peak and 29 minutes at 65% of VO2peak), and one day on the exercise bike (18x30 seconds at 90% of VO2peak and 36 minutes at 65% of VO2peak). -A hypocaloric and controlled sodium diet (3-6 g/day) was prescribed for each participant. -Supervised: fully.

Low volume HIIT
-Program duration: 24 weeks -Number of sessions: 5/week -Type of training: 5-10-minute warm-up and a 10-minute cool-down. One day on the treadmill (2x4 minutes at 90% of VO2peak and 12 minutes at 65% of VO2peak), and one day on the exercise bike (9x30 seconds at 90% of VO2peak and 15:30 minutes at 65% of VO2peak). -A hypocaloric and controlled sodium diet (3-6 g/day) was prescribed for each participant -Supervised: fully.

Diet
-No exercise -A hypocaloric and controlled sodium diet (3-6 g/day) was prescribed for each participant Diet+Exercise -Program duration: 24 weeks -Number of sessions: 5-7/week -Type of training: increase energy expenditure by 12.5% above baseline requirements by undergoing structured aerobic exercise (i.e., walking, running, or stationary cycling) 5 d/wk. Participants were allowed to select their exercise intensity (as long as their heart rate was within 65%-90% of maximal heart rate). -Supervision: partially.
-All diets were based on the American Heart Association Step 1 recommendations.

Control
General advices. Exercise -Program duration: 8 weeks -Number of sessions: 3/week -Type of training: 1) 5 min of warm-up; 2) 40 min of resistance training; 3) 20 min of aerobic exercise; 4) 5 min of cool-down. Three sets of 4 exercises. Rest between the sets of the exercise was set as 60-90 s. The repetition of resistance training was set as 15 reps a set at 70% 10RM intensity; 12 reps a set at 80% and 90% of 10RM intensity; and 10 reps a set at 100% of 10RM intensity. The aerobic exercise was performed on motorized treadmills for at least 20 min and the intensity of exer-cise was corresponding to approximately 60-85% of age-predicted maximal heart rate. -Supervision: partially.

Diet
-The participants consumed 25% of daily recommend energy intake in 3 days alternately on 'fast days' (400-500 kcal), and consumed ad libitum on the remaining 4 days of the week, known as 'feed days'.

Control
-Habitual lifestyle. week (10 minutes of warm-up training, 30 minutes of running with 50-70% of maximum heart rate and 5 minutes of cooling down), with the first two weeks exercising at 50% of maximum heart rate, in the second two weeks at 60%, in the third two weeks at 65%, and in the last two weeks at 70% of the maximum heart rate -Supervision: partially.

Control
-No exercise. Resistance Exercise -Program duration: 24 weeks -Number of sessions: 3/week -Type of training: using treadmills and elliptical trainers. Each exercise session included a 5-to 10-minute warm-up and a 5-to 10-minute cool-down. Women exercised at approximately 50% to 60% of their heart rate reserve (HRR) and gradually progressed in duration and intensity until they were able to exercise at more than 85% of their HRR for 45 minutes.. -Supervision: not reported.

Diet
Individuals were instructed to restrict their caloric intake by 300 to 500 kcal/d to achieve weight loss. Aerobic training -Program duration: 8 weeks -Number of sessions: 3/week -Type of training: 60 min treadmill or cycle ergometer. Starting at 40% of their heart rate reserve, participants were progressed to approximately 70% of their heart rate reserve. Participants could choose to exercise at a higher intensity but not to exceed 80% of their heart rate reserve.

Diet (N 9)
-Balanced diet to provide an energy deficit of 500-1.000 kcal/day from daily energy requirement -Diet + Exercise vs Diet -Intrahepatic fat -HOMA-IR -Systolic blood pressure -Diastolic blood pressure individual's 1-RM. After three sets at 80% of 1-RM (corresponding to a maximum of 8-12 repetitions  Within-groups comparison revealed that there were significant decrease in systolic blood pressure mean values between evaluation 1 (baseline) and evaluation 2 (end of treatment) in exercise groups, while there was non-significant increase in control group. Within-groups comparison revealed that there were significant decrease in DBP mean values between the 1 (baseline) and evaluation 2 (end of treatment), while there was non-significant increase in DBP of the control group.
Agree that results demonstrate small, but significant benefit from intervention. The results of the present trial emphasized that moderate-intensity continuous exercise three times per week for eight weeks (cycling exercise at 60-70% of max HR for 40-50 minutes) exhibited a definite decrease of hepatic triglycerides. The post-intervention outcomes showed significant differences in favor of the HII group.
Non-significant difference between mean changes in intervention and control group but significant difference in post intervention outcome. Diet-induced weight loss alone, but not exercise training alone, improved insulin sensitivity. Importantly, the combination of these two interventions resulted in an even greater improvement in insulin sensitivity at 12 months, a novel finding in this population, suggesting a distinct complementary effect of exercise training added to weight loss. In conclusion, lifestyle interventions associated with weight loss result in clinically important improvements in insulin sensitivity and multiple other cardio-metabolic risk factors in obese older adults.
Appropriate conclusions based on available data.  We have demonstrated in a randomized controlled study that 16 weeks of supervised moderateintensity aerobic exercise in NAFLD reduces liver fat. Intragroup comparisons showed that after 12 week of exercise, significant decreases in systolic blood pressure and diastolic blood pressure in all study groups. However, significantly reduced HOMA-IR was observed only in group 1 (Aerobic exercise).
Significant benefit from intervention despite small sample size. Figueroa et al, 2015 12 Pre vs. post ** Exercise-high ankle blood pressure Systolic blood pressure 143±4 vs. 132±4 Exercise-normal ankle blood pressure** Systolic blood pressure 134±2 vs. 122±4 Control ** Systolic blood pressure 139±3 vs. 141±3 Mean brachial systolic blood pressure was similarly decreased in the whole body vibration-high ankle-pressure and whole body vibration -normal ankle-pressure groups, respectively, compared with the control group. Control pre vs. post *** Blood pressure was significantly and similarly reduced in both intervention groups. Insulin resistance improved significantly and similarly in both intervention groups.
Appropriate conclusions based on available data.
No statistically significant differences were noted in median daily systolic blood pressure values between the groups both pre-and post-examination. Diastolic blood pressure was significantly (P <0.02) improved versus baseline only in the caloric restriction+exercise group but not in the caloric restriction group. Systolic blood pressure was not changed by any of the treatments.
Significant benefit from intervention and small sample size. The weight-loss protocol with a combination of Diet+Exercise had the strongest ameliorative effect on weight loss, being especially effective on blood pressure reduction, normalization of blood pressure, and insulin resistance. A 4 intervention groups experienced improvements in several risk factors. All experienced a decrease in systolic blood pressure and most experienced a decrease in diastolic blood pressure as well. The magnitudes of these changes are particularly significant, because no subject was enrolled with a starting blood pressure greater than 140/90 mmHg. Thus, even normotensive individuals experienced decreased blood pressure, which is associated with decreased risk of CVD and related diseases.
Appropriate conclusions based on available data. The main outcome was not the additive effect of exercise. The additive effect of exercise in reducing blood pressure is not so evident. In conclusion, a 12-week exercise program within Indigenous Australian men shows improvements in metabolic, anthropometric and fitness variables.
Negligible effect for the selected outcomes. Negligible differences between intervention and controls.