Clinical Trial Details
— Status: Active, not recruiting
Administrative data
| NCT number |
NCT04737694 |
| Other study ID # |
20-07HC |
| Secondary ID |
|
| Status |
Active, not recruiting |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
November 1, 2020 |
| Est. completion date |
September 1, 2022 |
Study information
| Verified date |
October 2021 |
| Source |
United States Army Research Institute of Environmental Medicine |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The objective of this randomized crossover study is to examine the influence of consuming a
ketone ester plus carbohydrate (KE+CHO) supplement on substrate oxidation and physical
performance in 15 healthy adults. Following a 48-hr muscle glycogen normalization period,
volunteers will consume either an isocaloric KE+CHO (KE: 573 mg KE/kg body mass, CHO: 110 g)
or isocaloric CHO drink and complete 90-min of metabolically-matched, load carriage (~30%
body mass) steady-state aerobic (~60 ± 5 % of VO2peak) exercise on a treadmill. Glucose
tracers will be used to assess glucose turnover, and contribution to exogenous and plasma
glucose oxidation. Serial blood draws will be collected during each trial to assess endocrine
and circulating substrate responses. After steady-state exercise volunteers will complete a
time to exhaustion (TTE) physical performance tests at 85% VO2peak on a treadmill. Volunteers
will then be provided with food for the remainder of the day. Following a 10-hr overnight
fast, volunteers will return to the laboratory and consume the same supplement (KE+CHO or
CHO) as they did the previous day. Volunteers will then perform a 4-mile load carriage time
trial on a treadmill. Following a minimum 7-day washout period, volunteers will return to the
laboratory to complete the second arm of the study. The primary risks associated with this
study include those associated with exercise, blood draws, and gastrointestinal discomfort
from the KE+CHO supplement.
Description:
Following an overnight (10 hour) fast, two catheters will be placed into the lower arm (one
in each arm). One arm will be used for infusion of 6,6-[2H2] glucose tracer and the other
will be used for blood sampling under resting and exercise conditions. Following an initial
blood sample collection to determine background enrichments, a primed, continuous infusion of
6,6-[2H2] glucose will begin (prime, 82.2 µmol∙kg-1; continuous rate, 0.78 µmol∙kg-1∙min-1,
Figure 1). The 6,6-[2H2] glucose will be infused for 100 min under resting fasted conditions
to ensure isotopic steady-state is achieved prior to initiating exercise. Volunteers will
consume either an isocaloric KE+CHO (KE: 573 mg KE/kg body mass, CHO: 110 g) or CHO drink
prior to and during 90-min of metabolically-matched (~60 ± 5 % of VO2peak), steady-state load
carriage (~30% body mass) exercise. Drinks will be enriched with U-13C-glucose (Cambridge
Isotope Laboratory, Andover, MA, USA) to increase the isotopic enrichment well above natural
levels and optimize the measurement of exogenous carbohydrate oxidation. During exercise
V̇O2, V̇CO2, and HR will be measured at approximately 0, 20, 45, 60, 75, and 85 min.
After the 90-min steady-state treadmill exercise, participants will complete a TTE
performance test. For volunteer safety TTE performance tests will be conducted without the
additional weight from the load carriage exercise. Volunteers will be given time to stretch
and warm-up on the treadmill before the TTE performance test beings. Volunteers will then run
on the treadmill at a fixed speed and grade that elicits 85% of their VO2peak. The TTE
performance test will be determined as the time of volitional exhaustion. Following
completion of the test, a self-selected cool-down will occur. Volunteers will complete a
minimum of two practice exercise sessions to ensure they are familiar with the performance
test.
The following day volunteers will return to the laboratory after an overnight fast. After
consuming the study drink (KE+CHO or CHO) participants will complete a self-paced 4-mile load
carriage (~30% body mass) time trial on a treadmill to assess aerobic performance. Time trial
performance will be assessed as the total amount of time taken to complete 4 miles. The
treadmill will be set at a constant 1% grade for the entire test. Following a warm-up period,
volunteers will blindly modulate treadmill speed in order to complete the distance as quickly
as possible. The only feedback given will be distance covered at half mile increments. At
half mile increments volunteers' rate of perceived exertion will be determined using the Borg
Scale. Heart rate will be monitored throughout the time trial. Heart rate will be recorded at
half mile increments. No motivation will be provided during the time trial. Participants may
consume water ad libitum during the time trial. Following completion of the test, a
self-selected cool-down will occur. Volunteers will complete a minimum of two practice
exercise sessions to ensure they are familiar with the performance test.
