Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT03798717 |
Other study ID # |
003AS |
Secondary ID |
|
Status |
Completed |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
February 20, 2019 |
Est. completion date |
March 9, 2020 |
Study information
Verified date |
July 2021 |
Source |
University of Portsmouth |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
Type 2 diabetes mellitus (T2DM) is characterised by chronic high blood sugar concentration
(hyperglycaemia) and insulin resistance leading to a reduction in insulin sensitivity. These
hyperglycaemic excursions can seriously impact metabolic, micro and macrovascular health. The
total cost of the direct and indirect care of individuals with diabetes (~90% T2DM) in the UK
(United Kingdom) is £23.7 billion, equating to ~20% of the annual national health service
(NHS) budget, with this projected to become unsustainable. Low-cost interventions to improve
glycaemic control in these individuals are therefore warranted. Current interventions include
pharmaceuticals, exercise and calorie restrictive diets. Pharmaceutical interventions carry a
high financial cost, while exercise and diet programmes have a low adherence rate in
individuals with T2DM.
Heat therapy offers one potential low cost therapy. Immersion in a hot tub for 30 mins.day-1
for 10 days has been shown to reduce fasting plasma [glucose] and HbA1c in individuals with
T2DM, which may be explained by acute (e.g. muscle) and chronic (e.g. reduced inflammatory
status and increased heat shock proteins (HSP)) adaptations, although experimental evidence
for these hypothesis are sparse. Other potential benefits include improved glycaemic control,
insulin sensitivity, elevated resting metabolic rate and improved micro- and macrovascular
function.
The aim of the present study is to determine whether acute hot water immersion can improve
glucose tolerance in individuals with T2DM and whether it is more beneficial to undertake
this before or after a OGTT (oral glucose tolerance test).
Description:
Visit 1 (consent, screening and familiarisation) During visit 1, participants will give their
informed consent, followed by a health screening questionnaire. In addition to the health
screening questionnaire, medical history and a blood sample will be collected and analysed
for a full blood count, glycated haemoglobin (HbA1c), liver and kidney function. Finally, a
resting electrocardiogram (ECG) will also be recorded and then examined for irregularities,
where a clinical decision will be made on further participation to the study by consultants
at QA (Queen Alexandra) hospital. Participants will then be shown the rest of the equipment
and taken through the procedure for the next 3 visits and, if the participant is happy to
continue the study, the next visit will be organised.
Visit 2, 3 and 4 Participants will arrive at the laboratory at ~9 am for conditions 1 and 2
and 8 am for condition 3. Prior to a 15 min resting period (supine) before any measures are
taken participants will be asked to insert a rectal thermistor (participants will be given
clear instructions using the investigator's SoPs (standard operating procedure)). Condition
1, 2 and 3 will be balanced and participants randomly allocated to begin the study in either
visit 2, 3 or 4 using a blinded member of the team.
For all visits (see figure 2), participants will lie in a semi recumbent position in minimal
clothing (bathing shorts and a t-shirt) for the entirety of the visit. Initially,
participants will be cannulated (Versatus winged and ported IV cannula, Terumo, Japan) and
blood samples drawn for analysis of osmolality (Lithium Heparin (LH) tubes BD (Becton,
Dickinson and Company), USA) plasma [glucose] (Fluoride/Oxalate tubes, BD, USA), [insulin]
(Ethylenediaminetetraacetic acid (EDTA) K2, BD, USA), and [eHSP70 (extracellular heat shock
protein 70)] (EDTA K2, BD, USA) at baseline and every 30 min of each experimental visit.
Following cannulation an 180 min OGTT (75g) (Rapilose OGTT solution, Penlan healthcare,
Japan) will commence in a thermoneutral room (~ 23oC). A maximum of 18 mL of blood being
drawn at each time point (max 126 mL per visit). To maintain the patency of the cannula and
to reduce the risk of infection, after every sample is taken, 5 mL of saline will be flushed
through the cannula. Then before every sample is taken, 2.5 mL of blood will be drawn out of
the cannula to ensure any remaining saline will not interfere with the samples and data
interpretation (additional 17.5mL per visit). During the OGTT, HR (heart rate) (via
electrocardiogram) will be measured continuously, whilst blood pressure (M5-1, Omron, Japan),
deep body temperature (rectal probe) and resting metabolic rate (indirect calorimetry) (Quark
CPET (cardiopulmonary exercise test), Cosmed, Italy) will be assessed every 30 min.
Condition 2 will employ identical procedures to condition 1, except thirty minutes into the
OGTT, the participant will be immersed into an immersion tank (~39oC) for 60 min. Water
temperature will be manipulated as required to achieve and maintain a target Trec at 38.5 oC
using water between 37.5 and 39oC, and then participants will be removed horizontally back
into the thermoneutral room for the reminder of the OGTT. Participants will be towel dried
and given a towelled robe to wear. Condition 3 will employ identical procedures to condition
2, with the exception that the heating via immersion will start as soon as the participant is
instrumented (and following a 15 min rest period) and the OGTT will commence 30 min after the
60 min immersion time for a further 180 min (see figure 2 for a schematic).