To identify the autonomic effects of recreationally-relevant doses of cannabidiol (CBD) in an older population, and to evaluate the effect of CBD on exercise performance and recovery.
Heart rate variability (HRV) analysis is a common method used to evaluate the function of the autonomic nervous system. While heart rate is the number of heart beats per minute, HRV is the fluctuation of the time intervals between those beats (interbeat intervals). If the interbeat intervals are too similar, this is an indication of an unhealthy heart. A major influence on heart rate (and thus interbeat interval), is the autonomic nervous system which is divided into two branches: sympathetic and parasympathetic. HRV represents the balance between both systems, with higher HRV being associated with greater parasympathetic activity, and lower HRV with greater sympathetic activity. While there is no optimal level of HRV, a higher HRV is associated with reduced stress and good health, and a lower HRV is associated with chronic diseases and cardiovascular risk. The current study will evaluate the effect of recreationally-relevant doses of CBD (25-200mg) on resting HRV in older adults (aims 1\&2). Investigators will also look at the effects of CBD on cardiovascular fitness by having participants complete a maximum graded exercise test under the influence of a placebo and again after ingesting a single dose of CBD (aims 3\&4).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Placebo oral product formulated in MCT (medium chain triglyceride) oil
Cannabidiol oral product formulated in MCT (medium chain triglyceride) oil
Castleton University, Jeffords Science Building
Castleton, Vermont, United States
Change in heart rate variability (HRV) as assessed by time-domain analysis: standard deviation of RR intervals.
Time-domain measurements quantify the amount of variability of the heart's interbeat (RR) intervals and include the metric: standard deviation of RR intervals (SDNN). Higher values indicate greater HRV.
Time frame: 4 weeks
Change in heart rate variability (HRV) as assessed by time-domain analysis: root mean square of successive differences.
Time-domain measurements quantify the amount of variability of the heart's interbeat (RR) intervals and include the metric: root mean square of successive differences (RMSSD). Higher values indicate greater HRV.
Time frame: 4 weeks
Change in heart rate variability (HRV) as assessed by frequency-domain analysis: high-frequency (HF).
Frequency-domain measurements estimate the distribution of absolute or relative power into four heart rate oscillation frequency bands: ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF) and high-frequency (HF). A high HF reflects parasympathetic dominance.
Time frame: 4 weeks
Change in heart rate variability (HRV) as assessed by frequency-domain analysis: low-frequency (LF).
Frequency-domain measurements estimate the distribution of absolute or relative power into four heart rate oscillation frequency bands: ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF) and high-frequency (HF). LF reflects both sympathetic and parasympathetic activity.
Time frame: 4 weeks
Change in heart rate variability (HRV) as assessed by frequency-domain analysis: LF/HF ratio.
A low LF/HF ratio reflects parasympathetic dominance, whereas a high LF/HF ratio reflects sympathetic dominance.
Time frame: 4 weeks
Change in magnitude of autonomic stress test responses as assessed by changes in blood pressure.
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Responses to autonomic stress test include a change in blood pressure if sympathetic outflow is activated. The magnitude of change will be compared before and after CBD ingestion.
Time frame: Week 5
Change in magnitude of autonomic stress test responses as assessed by changes in heart rate.
Responses to autonomic stress test include a change in heart rate if parasympathetic outflow is activated. The magnitude of change will be compared before and after CBD ingestion.
Time frame: Week 5
Maximal oxygen consumption (VO2max)
Maximum oxygen consumption will be calculated during treadmill test (using the Bruce Protocol)
Time frame: 8 days
Heart rate
Change in heart rate will be assessed throughout session
Time frame: through study completion, an average of 4 weeks
Blood pressure
Change in blood pressure will be assessed throughout session
Time frame: through study completion, an average of 4 weeks
Borg's Category-Ratio Scale for Rating of Perceived Exertion
The Borg Scale is a self-reporting instrument assessing intensity of perceived exertion on a 0 to 10 scale, 0 being rest and 10 maximal effort.
Time frame: 8 days