Effects of sauna and glucose intake on TSH and thyroid hormone levels in plasma of euthyroid subjects

Hot water immersion acutely reduces peripheral glucose uptake in young healthy males: An exploratory crossover randomized controlled trial

Whether glucose concentration increases during heat exposure because of reduced peripheral tissue uptake or enhanced appearance is currently unknown. This study aimed to report glucose concentrations in both capillary and venous blood in response to a glucose challenge during passive heating (PH) to assess whether heat exposure affects glucose uptake in healthy males. Twelve healthy male participants completed two experimental sessions, where they were asked to undertake an oral glucose tolerance test (OGTT) whilst immersed in thermoneutral (CON, 35.9 (0.6) °C) and hot water (HWI, 40.3 (0.5) °C) for 120 min. Venous and capillary blood [glucose], rectal temperature, and heart rate were recorded. [Glucose] area under the curve for HWI venous (907 (104) AU) differed from CON venous (719 (88) AU, all P < 0.001). No other differences were noted (P > 0.05). Compared with CON, HWI resulted in greater rectal temperature (37.1 (0.3) °C versus 38.6 (0.4) °C, respectively) and heart rate (69 (12) bpm versus 108 (11) bpm, respectively) on cessation (P < 0.001). An OGTT results in similar capillary [glucose] during hot and thermoneutral water immersion, whereas venous [glucose] was greater during HWI when compared with CON. This indicates that peripheral tissue glucose uptake is acutely reduced in response to HWI. Abbreviations: AUC: Area under the curve; CON: Thermoneutral immersion trial; HWI: Hot water immersion trial; OGTT: Oral glucose tolerance test; PH: Passive heating; T - m s k : Mean skin temperature; Trec: Rectal temperature.

Changes in Thyroid and Glycemic Status and Food Intake in Children with Excess Weight Who Were Submitted for a Multi-Component School Intervention for 16 Months

We investigated if children with excess weight who submitted to two types of intervention at school for 16 months showed improvements in thyroid and glycemic function and food intake. Children (8-11 years) with a body mass index-for-age (BMI/A) of ≥1 Z score were divided into two groups: Treatment 1 (n = 73) involved motivation to adopt healthier lifestyle; Treatment 2 (n = 103) involved performing weekly nutritional education, motivational, and physical activities at school. A semi-quantitative food frequency questionnaire was used. The delta BMI/A were similar after 16 months; Treatment 1 showed higher decrease in thyroid-stimulating hormone (TSH; median (range)): -0.45 (-3.19 to 2.17) and 0.06 (-4.57 to 1.63) mIU/L, p = 0.001), FreeT3 (-0.46 (-2.92 to 1.54) and -0.15 (-2.46 to 1.38) pmol/L, p = 0.038), and FreeT4 -1.41 (-6.18 to 3.47) and -0.90 (-4.89 to 2.96) pmol/L, p = 0.018), followed by decrease in energy intake (7304 (6806 to 7840) and 8267 (7739 to 8832) kJ, Ptreatment = 0.439, Ptime <0.001, interaction group-time p < 0.001), macronutrients and sugar. A positive correlation between FreeT3 and BMI/A, and a negative correlation with FreeT4 and insulin were found at baseline (r 0.212, p < 0.01; r -0.155, p < 0.01, respectively) and follow-up (r 0.222, p < 0.01; r -0.221, p < 0.01). The decrease in overall diet and particularly sugar intake was accompanied by a greater reduction in TSH and FreeT3 in Treatment 1, demonstrating the impact of dietary intake on thyroid function.

Association of Daily Home-Based Hot Water Bathing and Glycemic Control in Ambulatory Japanese Patients with Type 2 Diabetes Mellitus During the COVID-19 Pandemic: A Multicenter Cross-Sectional Study

PURPOSE

To clarify the relationship between daily hot water bathing (HWB) at home and glycemic control in middle-aged and elderly ambulatory patients with type 2 diabetes mellitus (T2DM).

METHODS

We defined hemoglobin A1c (HbA1c) as the main outcome. We set 7.0% based on the mean value of the dependent variable as the cut-off point for analysis. Frequency of HWB was an explanatory variable. A two-sample t-test was used to compare between groups with continuous variables. Multiple logistic regression analysis was performed for frequency, adjusted age, sex, BMI, T2DM duration (Model 1), and other confounding factors (Model 2). Odds ratio (OR) and 95% confidence interval (95% CI) were calculated.

RESULTS

Among 838 patients, there was a significant difference (p<0.001) in age between males (n=528, 62.8±8.7 years) and females (n=310, 65.0±8.1 years). In Model 1, compared with participants who used HWB more than seven times a week, those with poorly controlled HbA1c were significantly associated with low frequency of HWB: four to six times a week (OR 1.32, 95% CI 0.87-1.99) and less than three times a week (OR 1.43, 95% CI 0.98-2.10); p-value for overall trend was 0.041. In Model 2, p-value for overall trend was 0.138.

CONCLUSION

A higher frequency of HWB was moderately associated with a decreased risk of poor glycemic control in middle-aged and elderly ambulatory patients with T2DM.

Passive heating and glycaemic control in non-diabetic and diabetic individuals: A systematic review and meta-analysis

Objective

Passive heating (PH) has begun to gain research attention as an alternative therapy for cardio-metabolic diseases. Whether PH improves glycaemic control in diabetic and non-diabetic individuals is unknown. This study aims to review and conduct a meta-analysis of published literature relating to PH and glycaemic control.

Methods

Electronic data sources, PubMed, Embase and Web of Science from inception to July 2018 were searched for randomised controlled trials (RCT) studying the effect of PH on glycaemic control in diabetic or non-diabetic individuals. To measure the treatment effect, standardised mean differences (SMD) with 95% confidence intervals (CI) were calculated.

Results

Fourteen articles were included in the meta-analysis. Following a glucose load, glucose concentration was greater during PH in non-diabetic (SMD 0.75, 95% CI 1.02 to 0.48, P < 0.001) and diabetic individuals (SMD 0.27, 95% CI 0.52 to 0.02, P = 0.030). In non-diabetic individuals, glycaemic control did not differ between PH and control only (SMD 0.11, 95% CI 0.44 to -0.22, P > 0.050) and a glucose challenge given within 24 hours post-heating (SMD 0.30, 95% CI 0.62 to -0.02, P > 0.050).

Conclusion

PH preceded by a glucose load results in acute glucose intolerance in non-diabetic and diabetic individuals. However, heating a non-diabetic individual without a glucose load appears not to affect glycaemic control. Likewise, a glucose challenge given within 24 hours of a single-bout of heating does not affect glucose tolerance in non-diabetic individuals. Despite the promise PH may hold, no short-term benefit to glucose tolerance is observed in non-diabetic individuals. More research is needed to elucidate whether this alternative therapy benefits diabetic individuals.

Benefits and risks of sauna bathing

Although sauna bathing causes various acute, transient cardiovascular and hormonal changes, it is well tolerated by most healthy adults and children. Sauna bathing does not influence fertility and is safe during the uncomplicated pregnancies of healthy women. Some studies have suggested that long-term sauna bathing may help lower blood pressure in patients with hypertension and improve the left ventricular ejection fraction in patients with chronic congestive heart failure, but additional data are needed to confirm these findings. The transient improvements in pulmonary function that occur in the sauna may provide some relief to patients with asthma and chronic bronchitis. Sauna bathing may also alleviate pain and improve joint mobility in patients with rheumatic disease. Although sauna bathing does not cause drying of the skin-and may even benefit patients with psoriasis-sweating may increase itching in patients with atopic dermatitis. Contraindications to sauna bathing include unstable angina pectoris, recent myocardial infarction, and severe aortic stenosis. Sauna bathing is safe, however, for most people with coronary heart disease with stable angina pectoris or old myocardial infarction. Very few acute myocardial infarctions and sudden deaths occur in saunas, but alcohol consumption during sauna bathing increases the risk of hypotension, arrhythmia, and sudden death, and should be avoided.