Cannabis containing THC impairs 20-min cycling time trial performance irrespective of the method of inhalation.

Herein, we examine the human exercise response following cannabis inhalation, taking into consideration varied cannabinoid concentrations and different inhalation methods. A semirandomized crossover study design was used, with measures of perceived exertion and physiological responses to submaximal and maximal exercise. Participants (n = 14, 9 males 5 females) completed exercise after 1) smoking Δ-9-tetrahydrocannabinol (THC)-predominant cannabis (S-THC), 2) inhaling aerosol (vaporizing) from THC-predominant cannabis (V-THC), 3) inhaling aerosol from cannabidiol (CBD)-predominant cannabis (V-CBD), or 4) under control conditions. All exercise was performed on a cycle ergometer, with submaximal testing performed at 100 W followed by an evaluation of maximal exercise performance using an all-out 20-min time trial. Metabolism was characterized via the analysis of expired gases while subjective ratings of perceived exertion (RPE) were reported. During submaximal cycling, heart rate was higher during S-THC and V-THC compared with both control and V-CBD (all P < 0.02). During maximal exercise, V̇e was lower in V-THC compared with control, S-THC, and V-CBD (all P < 0.03), as was S-THC compared with control (P < 0.05). Both V̇o2 and RPE were similar between conditions during maximal exercise (both P > 0.1). Mean power output during the 20-min time trial was significantly lower in the S-THC and V-THC conditions compared with both control and V-CBD (all P < 0.04). Cannabis containing THC alters the physiological response to maximal and submaximal exercise, largely independent of the inhalation method. THC-containing cannabis negatively impacts vigorous exercise performance during a sustained 20-min effort, likely due to physiological and psychotropic effects. Inhalation of cannabis devoid of THC and primarily containing CBD has little physiological effect on the exercise response or performance.NEW & NOTEWORTHY Inhalation of cannabis containing THC alters physiological responses to both submaximal and maximal exercise and reduces mean power output during a 20-min time trial, regardless of whether it is inhaled as smoke or aerosol. In contrast, cannabis devoid of THC and predominantly containing CBD has no effect on physiological responses to exercise or performance.

Habitual cannabis use is associated with altered cardiac mechanics and arterial stiffness, but not endothelial function in young healthy smokers.

Cigarette smoking is among the most detrimental behaviors to cardiovascular health, resulting in arterial stiffening, endothelial dysfunction, and structural/functional alterations to the myocardium. Similar to cigarettes, cannabis is commonly smoked, and next to alcohol, is the most commonly used recreational substance in the world. Despite this, little is known about the long-term cardiovascular effects of smoking cannabis. This study explored the associations of cardiovascular structure and function with cannabis use in ostensibly healthy young participants (n = 35). Using echocardiography, carotid-femoral pulse wave velocity (cfPWV), and brachial flow-mediated dilation (FMD), we performed a cross-sectional assessment of cardiovascular function in cannabis users (n = 18) and controls (n = 17). There were no differences in cardiac morphology or traditional resting measures of systolic or diastolic function between cannabis users and controls (all P > 0.05), whereas cannabis users demonstrated reduced peak apical rotation compared with controls (cannabis users: 5.5 ± 3.8, controls: 9.6 ± 1.5; P = 0.02). Cannabis users had higher cfPWV compared with controls (cannabis users: 5.8 ± 0.6 m/s, controls: 5.3 ± 0.7 m/s; P = 0.05), whereas FMD was similar between cannabis users and controls (cannabis users: 8.3 ± 3.3%, controls: 6.8 ± 3.6%; P = 0.7). Young, healthy, and cannabis users demonstrate altered cardiac mechanics and greater aortic stiffness. Further studies should explore causal links between cannabis smoking and altered cardiovascular function.NEW & NOTEWORTHY Recreational cannabis is the most widely used substance in the world, other than alcohol. Yet, the effects of cannabis use on cardiovascular function and health are not well understood. Our cross-sectional data demonstrate that young, ostensibly healthy cannabis users have greater arterial stiffness and altered cardiac mechanics compared to nonusers. These findings suggest that cannabis users may be at greater risk of the development of future cardiovascular disease.

Vascular Function Is Differentially Altered by Distance after Prolonged Running.

PURPOSE: Ultraendurance exercise is steadily growing in popularity; however, the effect of increasingly prolonged durations of exercise on the vascular endothelium is unknown. The aim of this study was to characterize the effect of various ultramarathon running distances on vascular form and function. METHODS: We evaluated vascular endothelial function via flow-mediated dilation (FMD) in the superficial femoral artery, as well as microvascular function, inflammatory factors, and central artery stiffness, before and after participants completed 25-km (7M:2F), 50-km (11M:10F), 80-km (9M:4F), or 160-km (9M:2F) trail races all run on the same day and course. RESULTS: Completion required 149 ± 20, 386 ± 111, 704 ± 130, and 1470 ± 235 min, with corresponding average paces of 6.0 ± 0.8, 7.7 ± 2.2, 8.6 ± 1.3, and 9.6 ± 1.3 min·km-1, respectively. At baseline, there were no differences in participant characteristics across race distance groups. Shear rate stimulus trended toward an increase after the race (P = 0.07), but resting postrace artery diameter (P < 0.001) was elevated to a similar extent in all conditions. There was a reduction in FMD after the 50-km race (Δ -1.9% ± 2.2%, P < 0.01), but not the 25-km (Δ +0.3% ± 2.9%, P = 0.8), the 80-km (Δ -1.5% ± 3.2%, P = 0.1), or the 160-km (Δ +0.5% ± 2.5%, P = 0.5) race. Inflammatory markers increased most after 160 km, but arterial stiffness and microvascular function were not differently affected by race distance. CONCLUSIONS: Although the superficial femoral artery baseline diameter was larger postexercise regardless of race distance, only the 50-km race reduced FMD, whereas a short-duration higher-intensity race (25 km) and longer-duration lower-intensity races (160 km) did not. Therefore, a 50-km ultramarathon may represent the intersection between higher-intensity exercise over a prolonged duration, causing reduced endothelial function not seen in shorter or longer distances.

Prevalence of Indicators of Low Energy Availability in Elite Female Sprinters.

Low energy availability (LEA), and subsequent relative energy deficiency in sport, has been observed in endurance, aesthetic, and team sport athletes, with limited data on prevalence in athletes in short-burst activities such as sprinting. We examined prevalence of signs and symptoms of LEA in elite female sprinters at the start of the training season (PRE), and at the end of a 5-month indoor training period (POST). Four of 13 female sprinters (31%) presented at PRE testing with at least one primary (amenorrhea, low bone mineral density, low follicle-stimulating hormone, luteinizing hormone, or estradiol, resting metabolic rate ≤29 kcal/kg fat-free mass, Low Energy Availability in Females Questionnaire score ≥8) and one secondary indicator of LEA (fasting blood glucose <4 mmol/L, free triiodothyronine <3.5 pmol/L, ferritin <25 µg/L, low-density lipoprotein cholesterol >3.0 mmol/L, fasting insulin <20 pmol/L, low insulin-like growth factor-1, systolic blood pressure <90 mmHg, and/or diastolic blood pressure <60 mmHg). At POST, seven out of 13 athletes (54%) presented with at least one primary and one secondary indicator of LEA, three of whom had also presented with indicators of LEA at PRE. Five out of 13 (39%) athletes had previous stress fracture history, though this was not associated with current indicators of LEA (PRE: r = .52, p = .07; POST: r = -.07, p = .82). In conclusion, elite female sprinters may present with signs and symptoms of LEA, even after off-season rest. Medical and coaching staff should be aware of the signs and symptoms of LEA and relative energy deficiency in sport and should include appropriate screening and intervention strategies when working with sprinters.