Healthy
Conditions
Brief summary
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.
Detailed description
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).
Interventions
DRUGPlacebo
Placebo oral product formulated in MCT (medium chain triglyceride) oil
DRUGCannabidiol
Cannabidiol oral product formulated in MCT (medium chain triglyceride) oil
Sponsors
Castleton University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Intervention model description
Each participant will receive a different dose in consecutive weeks (one of which is a placebo), thus serving as their own control.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* male or female * 18+ years (aims 3&4) * 50+ years (aims 1&2) * participants must agree to fast for 4 hours and abstain from food or beverages containing alcohol, caffeine, or CBD for 12 hours prior to each experimental session * participants must agree to avoid exercise for 6 hours prior to each experimental session * completion of Health History Screening Questionnaire with report indicating overall good health * ability to comprehend and satisfactorily comply with protocol requirements * written informed consent given prior to study participation * low-risk for VO2max testing (aims 3&4)
Exclusion criteria
* women who are pregnant or lactating * participants who have a history of adverse reactions to cannabidiol * current medications that might influence the cardiovascular and/or autonomic systems * any cardiac, pulmonary, renal, or metabolic disease * walking difficulty (aims 3&4) * waiting for a stress test for a medical reason (aims 3&4) * medical contraindication to performing a treadmill stress test (aims 3&4)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in magnitude of autonomic stress test responses as assessed by changes in blood pressure. | Week 5 | 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. |
| Maximal oxygen consumption (VO2max) | 8 days | Maximum oxygen consumption will be calculated during treadmill test (using the Bruce Protocol) |
| Heart rate | through study completion, an average of 4 weeks | Change in heart rate will be assessed throughout session |
| Change in heart rate variability (HRV) as assessed by time-domain analysis: standard deviation of RR intervals. | 4 weeks | 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. |
| Change in heart rate variability (HRV) as assessed by time-domain analysis: root mean square of successive differences. | 4 weeks | 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. |
| Change in heart rate variability (HRV) as assessed by frequency-domain analysis: high-frequency (HF). | 4 weeks | 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. |
| Change in heart rate variability (HRV) as assessed by frequency-domain analysis: low-frequency (LF). | 4 weeks | 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. |
| Change in heart rate variability (HRV) as assessed by frequency-domain analysis: LF/HF ratio. | 4 weeks | A low LF/HF ratio reflects parasympathetic dominance, whereas a high LF/HF ratio reflects sympathetic dominance. |
| Change in magnitude of autonomic stress test responses as assessed by changes in heart rate. | Week 5 | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Borg's Category-Ratio Scale for Rating of Perceived Exertion | 8 days | 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. |
| Blood pressure | through study completion, an average of 4 weeks | Change in blood pressure will be assessed throughout session |
Other
| Measure | Time frame | Description |
|---|---|---|
| Breathing frequency | 8 days | Breathing frequency will be measured throughout session |
| Blood lactate | 8 days | Plasma lactate assess by finger stick |
| Change in oxygen saturation | 8 days | percent O2 saturation measured by pulse oximeter throughout session |
| Tidal volume | 8 days | Tidal volume will be measured throughout session |
| Change in exercise duration | 8 days | Total exercise time on the treadmill while performing the Bruce Protocol. |
Countries
United States
Outcome results
None listed