Interaction between leptin and leisure-time physical activity and development of hypertension

Long-Distance Skiing and Incidence of Hypertension: A Cohort Study of 206 889 Participants in a Long-Distance Cross-Country Skiing Event

BACKGROUND

Hypertension is the leading risk factor for death worldwide, and high levels of physical activity are associated with a lower incidence of hypertension. The associations of excessive levels of exercise and incidence of hypertension are less well known. We aim to compare the incidence of hypertension among 206 889 participants in a long-distance cross-country skiing event and 505 542 people randomly sampled from the general population (matched to the skiers on age, sex, and place of residence).

METHODS

Skiers' best performance (in percent of winning time) and number of completed races during the study period were associated with incidence of hypertension after participation in Vasaloppet. Hypertension was defined as prescription of blood pressure-lowering drugs as obtained from the national drug registry. Models were adjusted for sex, age, education, and income (total effect).

RESULTS

During a median time of risk of 8.3 years, skiers had a lower incidence of hypertension compared with nonskiers (hazard ratio [HR], 0.59 [95% CI, 0.58-0.60]). Among the skiers, better performance (in percent of winning time) in Vasaloppet was strongly associated with a lower incidence of hypertension (fastest fifth: HR, 0.41 [95% CI, 0.39-0.42]; slowest fifth: HR, 0.78 [95% CI, 0.75-0.81]). The association was nearly linear and did not differ between sexes. Among the skiers, a weaker association was seen between the number of completed races during the study period and the incidence of hypertension (1 race: HR, 0.63 [95% CI, 0.62-0.65]; >5 races: HR, 0.51 [95% CI, 0.50-0.53]). A subanalysis of 10 804 participants including adjustment for lifestyle factors showed similar results.

CONCLUSIONS

Participation in a long-distance skiing event was associated with a 41% lower incidence of hypertension over the next 8 years compared with nonparticipation. A near linear association between performance and incidence of hypertension was observed. This adds to the list of beneficial effects of intensive training, because hypertension is the leading risk factor of premature death globally.

Exercise addiction in men is associated with lower fat-adjusted leptin levels

OBJECTIVE

To test a hypothesized association between resting leptin levels (adjusted for body fat percentage) and symptoms of primary exercise addiction.

DESIGN

Cross-sectional design.

SETTING

Habitual amateur exercisers participating in running, fitness, weight training, and biking.

PARTICIPANTS

Twenty men with exercise addiction as defined by the Exercise Addiction Inventory (EAI scores 24-30) and 20 men in an exercise control group (EAI scores 6-16) matched on body mass index.

MAIN OUTCOME MEASURES

Plasma leptin and sex hormones were measured in blood samples collected under fasting and resting conditions. Body composition was assessed by dual-energy x-ray absorptiometry. Eating disorder symptoms were identified by the Eating Disorder Inventory 2.

RESULTS

The exercise addiction group had significantly (P < 0.001) lower leptin levels (1.1 μg/L, SD = 1.3) than controls (4.3 μg/L, SD = 2.9). Even when adjusted for body fat percentage, the addiction group had significantly (P < 0.001) lower leptin levels (0.1 μg/L, SD = 0.1) than the controls (0.2 μg/L, SD = 0.1). Body fat-adjusted leptin correlated with free bioavailable testosterone, but it was only significant in nonaddictive exercisers. None of the exercisers seemed to suffer from an eating disorder.

CONCLUSIONS

This is the first study showing that excessive training in exercise addiction is associated with low levels of body fat-adjusted leptin levels.

CLINICAL RELEVANCE

Hypoleptinemia could be involved in the pathogenesis of exercise addiction. However, further studies are needed to explore the potential causal relationship.

Physical activity and the prevention of hypertension

As the worldwide prevalence of hypertension continues to increase, the primary prevention of hypertension has become an important global public health initiative. Physical activity is commonly recommended as an important lifestyle modification that may aid in the prevention of hypertension. Recent epidemiologic evidence has demonstrated a consistent, temporal, and dose-dependent relationship between physical activity and the development of hypertension. Experimental evidence from interventional studies has further confirmed a relationship between physical activity and hypertension as the favorable effects of exercise on blood pressure reduction have been well characterized in recent years. Despite the available evidence strongly supporting a role for physical activity in the prevention of hypertension, many unanswered questions regarding the protective benefits of physical activity in high-risk individuals, the factors that may moderate the relationship between physical activity and hypertension, and the optimal prescription for hypertension prevention remain. We review the most recent evidence for the role of physical activity in the prevention of hypertension and discuss recent studies that have sought to address these unanswered questions.

Physical activity and risk of hypertension: a meta-analysis of prospective cohort studies

Published literature reports controversial results about the association of physical activity (PA) with risk of hypertension. A meta-analysis of prospective cohort studies was performed to investigate the effect of PA on hypertension risk. PubMed and Embase databases were searched to identify all related prospective cohort studies. The Q test and I(2) statistic were used to examine between-study heterogeneity. Fixed or random effects models were selected based on study heterogeneity. A funnel plot and modified Egger linear regression test were used to estimate publication bias. Thirteen prospective cohort studies were identified, including 136,846 persons who were initially free of hypertension, and 15,607 persons developed hypertension during follow-up. The pooled relative risk (RR) of main results from these studies suggests that both high and moderate levels of recreational PA were associated with decreased risk of hypertension (high versus low: RR, 0.81; 95% confidence interval, 0.76-0.85 and moderate versus low: RR, 0.89; 95% confidence interval, 0.85-0.94). The association of high or moderate occupational PA with decreased hypertension risk was not significant (high versus low: RR, 0.93; 95% confidence interval, 0.81-1.08 and moderate versus low: RR, 0.96; 95% confidence interval, 0.87-1.06). No publication bias was observed. The results of this meta-analysis suggested that there was an inverse dose-response association between levels of recreational PA and risk of hypertension, whereas there was no significant association between occupational PA and hypertension.

Increased circulating ANG II and TNF-α represents important risk factors in obese saudi adults with hypertension irrespective of diabetic status and BMI

Central adiposity is a significant determinant of obesity-related hypertension risk, which may arise due to the pathogenic inflammatory nature of the abdominal fat depot. However, the influence of pro-inflammatory adipokines on blood pressure in the obese hypertensive phenotype has not been well established in Saudi subjects. As such, our study investigated whether inflammatory factors may represent useful biomarkers to delineate hypertension risk in a Saudi cohort with and without hypertension and/or diabetes mellitus type 2 (DMT2). Subjects were subdivided into four groups: healthy lean controls (age: 47.9±5.1 yr; BMI: 22.9±2.1 Kg/m²), non-hypertensive obese (age: 46.1±5.0 yr; BMI: 33.7±4.2 Kg/m²), hypertensive obese (age: 48.6±6.1 yr; BMI: 36.5±7.7 Kg/m²) and hypertensive obese with DMT2 (age: 50.8±6.0 yr; BMI: 35.3±6.7 Kg/m²). Anthropometric data were collected from all subjects and fasting blood samples were utilized for biochemical analysis. Serum angiotensin II (ANG II) levels were elevated in hypertensive obese (p<0.05) and hypertensive obese with DMT2 (p<0.001) compared with normotensive controls. Systolic blood pressure was positively associated with BMI (p<0.001), glucose (p<0.001), insulin (p<0.05), HOMA-IR (p<0.001), leptin (p<0.01), TNF-α (p<0.001) and ANG II (p<0.05). Associations between ANG II and TNF-α with systolic blood pressure remained significant after controlling for BMI. Additionally CRP (p<0.05), leptin (p<0.001) and leptin/adiponectin ratio (p<0.001) were also significantly associated with the hypertension phenotype. In conclusion our data suggests that circulating pro-inflammatory adipokines, particularly ANG II and, TNF-α, represent important factors associated with a hypertension phenotype and may directly contribute to predicting and exacerbating hypertension risk.