2134/10007966.v1
Christof Leicht
Christof
Leicht
Lewis James
Lewis
James
Jane Helen Blythe Briscoe
Jane Helen Blythe
Briscoe
Sven Hoekstra
Sven
Hoekstra
Hot water immersion acutely increases postprandial glucose concentrations
Loughborough University
2019
Clinical Sciences
Medical Physiology
hyperthermia
temperature
glycaemic control
hot water therapy
passive heating
Physiology
2019-10-22 12:33:24
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/Hot_water_immersion_acutely_increases_postprandial_glucose_concentrations/10007966
Background: Chronic hot water immersion (HWI) confers health benefits, including a reduction
in fasting blood glucose concentration. Here we investigate acute glycaemic control immediately
after HWI. Methods: Ten participants (age: 25 ± 6 years, body mass: 84 ± 14 kg, height 1.85 ±
0.09 m) were immersed in water (39ºC) to the neck (HWI) or sat at room temperature (CON) for
60 min. One hour afterwards they underwent an oral glucose tolerance test (OGTT), with blood
collected before and after HWI/CON and during the 2 h OGTT. Results: Glucose incremental
area under the curve (iAUC) during the OGTT was higher for HWI (HWI 233 ± 88, CON 156 ±
79 mmol·L-1·2h, P = 0.02). Insulin iAUC did not differ between conditions (HWI 4309 ± 3660,
CON 3893 ± 3031 mU·L-1·2h, P=0.32). Core temperature increased to 38.6 ± 0.2°C during HWI,
but was similar between trials during the OGTT (HWI 37.0 ± 0.2, CON 36.9 ± 0.4°C, P=0.34).
Directly following HWI, plasma average adrenaline and growth hormone concentrations
increased 2.7 and 10.7-fold, respectively (P < 0.001). Plasma glucagon like peptide-1, peptide
YY and acylated ghrelin concentrations were not different between trials during the OGTT (P >
0.11). Conclusions: HWI increased postprandial glucose concentration to an OGTT, which was
accompanied by acute elevations of stress hormones following HWI. The altered glycaemic
control appears to be unrelated to changes in gut hormones during the OGTT.