Primary objective:o To evaluate the effect of mild heat acclimation on insulin sensitivity in obese men and womenSecondary objectives:o To evaluate the effect of mild heat acclimation on insulin signalling and heat shock protein expression in human…
ID
Source
Brief title
Condition
- Glucose metabolism disorders (incl diabetes mellitus)
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Main study parameter/endpoint
o Insulin sensitivity
Secondary outcome
Secondary study parameters/endpoints
o Insulin signalling and heat shock protein expression in human muscle
o Energy expenditure
o Total sweat loss and sweat rate
o Core body temperature, skin temperature distribution and skin blood flow
o Cardiovascular parameters (blood pressure, heart rate and cardiac output)
o Subjective perception of the thermal environment
Other study parameters (if applicable)
o Body composition (DEXA)
o Glucose tolerance (OGTT)
Background summary
Recent studies evidenced the positive effect of heat treatment on insulin
resistance in rodents. Heat treatment, more specifically hot water immersion of
the lower body, improved insulin signalling and increased heat shock protein 72
expression in diabetic rodent muscle tissue. Heat shock protein expression
positively correlates with increased glucose metabolism and is therefore
anticipated to participate in insulin signalling mechanisms. However, human
data is very limited. We have recently shown that relatively mild passive heat
acclimation in young healthy subjects evokes in part similar physiological
adaptations as accomplished by more intense combined heat acclimation and
exercise studies. For instance, mild heat acclimation induced a decrease in
core temperature and evoked an earlier increase of energy expenditure upon
exposure to warm temperatures.
We therefore hypothesize, that in obese subject with high risk for the
development of pre-diabetes (impaired fasting glucose, IFG and/or impaired
glucose tolerance, IGT) or diabetes, passive mild heat acclimation (35*C) will
improve insulin signalling, which might improve insulin resistance and thereby
reduce the risk for the development of the respective symptoms and diseases.
Study objective
Primary objective:
o To evaluate the effect of mild heat acclimation on insulin sensitivity in
obese men and women
Secondary objectives:
o To evaluate the effect of mild heat acclimation on insulin signalling and
heat shock protein expression in human muscle tissue of obese men and women
o To evaluate the effect of mild heat acclimation on energy expenditure
during heat exposure in obese men and women
o To evaluate the effect of mild heat acclimation on total sweat loss and sweat
rate during heat exposure in obese men and women
o To evaluate the effect of mild heat acclimation on core temperature, skin
temperature distribution and skin blood flow during heat exposure in obese men
and women
o To evaluate the effect of mild heat acclimation on cardiovascular parameters
during heat exposure inobese men and women
o To evaluate the effect of mild heat acclimation on subjective perception of
the thermal environment during heat exposure in obese men and women
Study design
The study will be carried out in a pre-test/post-test design. 13 obese men and
women (BMI between 25-35kg/m2) will be included after being screened for in-
and exclusion criteria. If eligibility is assessed, volunteers will be invited
to participate for 12 consecutive study days, whereof 4 measurement days (2
full measurement days (1 and 12, each 8h) and 2 half measurement days (2 and
11, each 3.5h)) and 10 days of mild heat acclimation (8 full (6h) and 2 half
acclimation days (4h)).
Intervention
The intervention consists of 10 days (2 half days (4h) and 8 full days (6h)) of
passive mild heat acclimation to 35*C.
Study burden and risks
Although complications are rare, each measurement involves some risks. During
hyperinsulinemic euglycemic clamp subjects might exhibit symptoms of
hypoglycaemia. Muscle biopsies might be complicated by bleeding, infection or
nerve damage. After the local anaesthetics wear off, subjects might exhibit
pain. The intravenous cannula used during the clamp may cause a haematoma. The
effective dose of the DXA-scan is 1-7 microSievert and this is considered as a
low risk.There are no personal benefits associated with participation, but
participation can help to gain more knowledge about the effects of heat
acclimation on insulin sensitivity in prediabetic persons. The intervention may
affect or improve the glucose metabolism, but this is not certain. The
investigators will provide the participants with their study results after the
study is finished, if they wish so.
Minderbroedersberg 4-6
Maastricht 6211LK
NL
Minderbroedersberg 4-6
Maastricht 6211LK
NL
Listed location countries
Age
Inclusion criteria
o Men and women
o Caucasian race
o Age 40-70 years
o BMI between 25 and 35 kg/m2
o Steady dietary habits
o Generally healthy, no medication use that interferes with metabolism. If volunteers need medication (e.g. statin drugs, NSAIDs), it will be reviewed with the dependent physician on individual basis.
o Women after their menopause, meaning no menstrual cycle for at least 24 months and only if they are not under hormonal treatment.
Exclusion criteria
o Haemoglobin <8.4mmol/L
o No signs of active uncontrolled hypertension, liver of kidney malfunction
o Cardiac problems and cardiovascular diseases, such as angina pectoris, cardiac infarction and arrhythmias
o Any medical condition requiring treatment and/or medication that interferes with investigated parameters. Medical conditions and treatments will be discussed with the dependent physician on individual basis
o Anticoagulation medication
o Unstable body weight (weight gain or loss >3kg in the past three months)
o Participation in another biomedical study within 1 month prior to screening visit
o Volunteers, who do not want to be informed about unexpected medical findings, or do not wish that their treating physician will be informed, cannot participate in this study
o Blood donation three month prior to study and three month after finishing study
o Women will be excluded if their last menstrual cyclus was less than 24 months ago and if they are under hormonal treatment (to alleviate symptoms of the menopause).
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
In other registers
| Register | ID |
|---|---|
| CCMO | NL56876.068.16 |
| OMON | NL-OMON27050 |