Treatment response heterogeneity and individual responses following exercise training are topics of interest for personalized medicine. Proposed methods to determine the contribution of exercise to the magnitude of treatment response heterogeneity and categorizing participants have expanded and evolved. Setting clear research objectives and having a comprehensive understanding of the strengths and weaknesses of the available methods are vital to ensure the correct study design and analytical approach are used. Doing so will ensure contributions to the field are conducted as rigorously as possible. Nonetheless, concerns have emerged regarding the ability to truly isolate the impact of exercise training, and the nature of individual responses in relation to mean group changes. The purpose of this review is threefold. First, the strengths and limitations associated with current methods for quantifying the contribution of exercise to observed treatment response heterogeneity will be discussed. Second, current methods used to categorize participants based on their response to exercise will be outlined, as well as proposed mechanisms for factors that contribute to response variation. Finally, this review will provide an overview of some current issues at the forefront of individual response research.

The rapidly increasing skin cancer rates in Canada are alarming, with current data estimating that 1/3 of Canadians will be affected in their lifetime. Thus, deeper understanding of high-risk sun exposure behaviors is needed to help counter this trend. Only limited action has been taken by federal/provincial governments to reduce skin cancer incidence. A cross-sectional survey study was conducted in Manitoba, with frequency counts, means, and percentages used to encapsulate responses. Age- and gender-adjusted odds ratios were calculated using logistic regression analyses. Our study identified worrying inadequacies in sun protective behaviors and attitudes, with the threat of such high-risk behaviors amplified by a lack of skin cancer awareness. Alarming elements were noted in participants’ sun exposure history (>65% reported a history of sunburns, >50% previously used a tanning bed, and >75% recently tanned for pleasure), beliefs and attitudes (>50% believe that they look better/healthier with a tan, and >40% believe that having a base tan is protective against further sun damage), and sun protection efforts (sun protective clothing was used <60% of the time, sunscreen was used by <50%, and there was a lack of knowledge about sunscreen characteristics in ~30% of respondents), in addition to significant differences being established between demographic subgroups (based on gender, age, skin phototype, income, and education attained). This study provides worrisome insight onto the grim landscape of sun protective behaviors and attitudes in Manitoba, which will inevitably translate into higher skin cancer rates and should serve as a call to action to promote targeted public health messaging in this jurisdiction and beyond.

Background: Skin cancer prevention relies on effective sun safety practices. Previous studies have shown that LGBTQ+ individuals exhibit lower sunscreen use and higher tanning bed usage compared to their non-LGBTQ+ counterparts. This study is the first to assess skin cancer risk factors, sun-protective behaviors, and skin cancer concerns among LGBTQ+ individuals across Canada. Methods: A national survey study was conducted between July 2020 and March 2024 and included LGBTQ+ respondents aged ≥ 16 years who had completed the survey. Responses were summarized using frequency counts/percentages for categorical variables and means/standard deviations for continuous variables. Logistic regression models were used to calculate age- and gender-adjusted odds ratios for subgroup analyses. Results: Of the 700 LGBTQ+ participants included (59.3% women; median age 38 years), the majority had a Fitzpatrick skin phototype (FSP) I–III (76.4%). Concerningly, 60% reported >10 lifetime sunburns, 58% reported ≥1 blistering sunburn, 34% had used a tanning bed ≥1 time in their lifetime, and 69% reported having a tan in the last 12 months. Sunscreen was worn regularly by only half of the respondents, and half of the participants agreed or strongly agreed with “I look better and/or healthier with a tan”. Additional comparisons are presented based on gender, FSP, education, and income. Conclusion: The findings of this study highlight the need for public health campaigns tailored to the LGBTQ+ community, emphasizing culturally sensitive sun safety education, particularly for LGBTQ+ men, individuals with FSP IV–VI, and those with lower education levels, to help reduce future skin cancer risk.

This study determined the interindividual variation in the cardiometabolic response to 6 months of moderate or vigorous intensity exercise training (ET) among youth at risk for type 2 diabetes mellitus. Youth were randomized to moderate intensity ET (45–55% heart rate reserve; n = 31), vigorous intensity ET (70–85% heart rate reserve; n = 37), or control (n = 36). Only those attending ≥70% of ET sessions were included. Cardiometabolic measures included insulin sensitivity, hepatic triglyceride content, visceral adipose area, and cardiorespiratory fitness. The contribution of ET to interindividual variation was determined using the standard deviation of individual responses (SD_IR) and considered meaningful if the SD_IR surpassed the smallest worthwhile difference (SWD), calculated as 0.2 × the standard deviation of the control group baseline values. ET meaningfully contributed to the interindividual variation among changes in peak oxygen uptake following moderate (SD_IR: 2.04) and vigorous (SD_IR: 3.43) ET (SWD: 1.17 mL·kg fat free mass⁻¹·min⁻¹), body fat percentage and hepatic triglyceride content following moderate-intensity ET (SD_IR: 1.64, SWD: 1.05%; SD_IR: 10.08, SWD: 1.06%, respectively), and visceral fat mass following vigorous ET (SD_IR: 11.06, SWD: 7.13 cm²). Variation in the changes in insulin sensitivity were not influenced by ET. The contribution of ET to interindividual variation appears to be influenced by the desired outcome and prescribed intensity. Trial registration at ClinicalTrials.gov (identifier no.: NCT00755547). Novelty: The contribution of exercise to interindividual variation following training depends on the outcome and exercise intensity. Increasing exercise intensity does not systematically reduce non-response among youth at risk for type 2 diabetes.