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Jenna Stone

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Affiliations

  • PhD Candidate at McMaster University

Education

  • BSc from McMaster University

  • PhD from McMaster University

Email

Lab Website

Research

Jenna Stone is investigating the impact of sex hormones, including those found in hormonal contraceptives, on early risk factors for cardiovascular disease in women. Stone, a PhD candidate in the Vascular Dynamics Lab, is working under the supervision of Maureen MacDonald, the dean of the Faculty of Science.

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Resources I Recommend

This study analyzed 514 research papers spanning 26 years to assess the inclusion of male and female participants in studies on exercise and vascular endothelial function. They found a significant male bias, with 64% male participants compared to 36% female. Male-only studies were more common (32%) than female-only studies (12%). Despite efforts, the proportion of female participants remained stable over time. Male-only studies were less likely to mention sex in titles or abstracts and more likely to justify exclusion based on sex. Reasons for sex-specific inclusion/exclusion included literature gaps, hormonal cycle considerations, adherence to male norms, and recruitment/retention challenges. 

Vascular endothelial and smooth muscle cell dysfunction proceed the development of numerous vascular diseases, such as atherosclerosis. Both estrogen and progesterone receptors are present on vascular endothelial and smooth muscle cells, and therefore it has been postulated that these compounds may affect vascular function. It has been well-established that estrogen is a vasoprotective compound, however, the effects of progesterone on vascular function are not well understood. This narrative review summarizes the current research investigating the impact of both endogenous progesterone, and exogenous synthetic progestin on vascular endothelial and smooth muscle cell function and identifies discrepancies on their effects in vitro and in vivo. We speculate that an inverted-U dose response curve may exist between nitric oxide bioavailability and progesterone concentration, and that the androgenic properties of a progestin may influence vascular function. Future research is needed to discern the effects of both endogenous progesterone and exogenous progestin on vascular endothelial and smooth muscle cell function with consideration for the impacts of progesterone/progestin dose, and progestin type.

This study investigated how the natural menstrual cycle (NAT) and different oral contraceptive pills (OCP2 and OCP3) affect substrate oxidation during rest and submaximal aerobic exercise in females. Fifty participants were divided into three groups based on their contraceptive method. Results showed no significant differences in respiratory exchange ratio (RER) or carbohydrate and lipid oxidation rates between low and high hormone phases during rest or exercise. The only notable difference was higher carbohydrate oxidation in NAT compared to OCP2 during exercise. Overall, NAT and OCPs did not significantly influence substrate oxidation during rest or acute submaximal aerobic exercise.

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