Browsing by Author "Rae, Dale E"

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    A sleep behaviour intervention to improve cardiometabolic health in adults with overweight and obesity
    (2020) Henst, Rob HP; Rae, Dale E; Roden, Laura C
    Rob Henricus Petrus Henst was born on the 12th of March in Schaijk, the Netherlands. He graduated from pre-vocational secondary education (VMBO) in 2005 and continued to study process and laboratory technology at an intermediate vocational educational (MBO) institution. In 2009, Rob started with a Bachelor of Science degree, majoring in Life Science with a minor in Exercise Science. For his undergraduate thesis in 2012, he moved to South Africa where he was introduced to chronobiology in exercise science. In 2013, Rob continued to study in South Africa for his Master of Science (Exercise Science) degree and published his first peer-reviewed article in the Journal of Biological Rhythms. He then developed an interest in sleep and cardiometabolic health, specifically in the context of public health. In 2015, these interests were combined and lead to his current PhD thesis on a sleep behaviour intervention for the betterment of cardiometabolic health. In this year, he also co-founded the business unit Sleep Science within the Sports Science Institute of South Africa to help individuals sleep better. In 2019, Rob moved back to the Netherlands to write the final pages of his PhD thesis.
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    Cross-sectional associations between mental health indicators and social vulnerability, with physical activity, sedentary behaviour and sleep in urban African young women
    (2022-07-10) Draper, Catherine E; Cook, Caylee J; Redinger, Stephanie; Rochat, Tamsen; Prioreschi, Alessandra; Rae, Dale E; Ware, Lisa J; Lye, Stephen J; Norris, Shane A
    Background Relationships between mental health and multiple health behaviours have not been explored in young South African women experiencing social constraints. The aim of this study was to identify associations between mental health indicators and risk factors with physical activity, sedentary behaviour, and sleep, amongst young women living in Soweto, a predominantly low-income, urban South African setting. Methods For this cross-sectional study, baseline measurements for participants (n = 1719, 18.0–25.9 years old) recruited for the Healthy Life Trajectories Initiative were used including: physical activity, sedentary behaviour (sitting, screen and television time), sleep (duration and quality), depression and anxiety indicators, emotional health, adverse childhood experiences, alcohol-use risk; social vulnerability, self-efficacy, and social support. Results Multiple regression analyses showed that depression (β = 0.161, p < 0.001), anxiety (β = 0.126, p = 0.001), adverse childhood experiences (β = 0.076, p = 0.014), and alcohol-use risk (β = 0.089, p = 0.002) were associated with poor quality sleep. Alcohol-use risk was associated with more screen time (β = 0.105, p < 0.001) and television time (β = 0.075, p < 0.016). Social vulnerability was associated with lower sitting time (β = − 0.187, p < 0001) and screen time (β = − 0.014, p < 0.001). Higher self-efficacy was associated with more moderate- to vigorous-intensity physical activity (β = 0.07, p = 0.036), better-quality sleep (β = − 0.069, p = 0.020) and less television time (β = − 0.079, p = 0.012). Having no family support was associated with more sitting time (β = 0.075, p = 0.022). Binomial logistic regression analyses supported these findings regarding sleep quality, with anxiety and depression risk doubling the risk of poor-quality sleep (OR = 2.425, p < 0.001, OR = 2.036, p = 0.003 respectively). Conclusions These findings contribute to our understanding of how mental health indicators and risk factors can be barriers to health behaviours of young women in Soweto, and that self-efficacy and social support can be protective for certain of these behaviours for these women. Our results highlight the uniqueness of this setting regarding associations between mental health and behaviours associated with non-communicable diseases risk.
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    PERIOD3 variable number tandem repeat genotype associations with performance, injury, illness and re-entrainment
    (2016) Kunorozva, Lovemore; Roden, Laura C; Rae, Dale E
    Background: Circadian rhythms are internally driven biological variations that fluctuate with a period of approximately 24 hours, even in the absence of external environmental time cues. These rhythms enable organisms to synchronise their internal clock time with external environmental time. This ensures appropriate timing of biological and metabolic processes, and allows anticipation of daily changes in the environment. Circadian rhythms also play an important role in sports in terms of optimising performance time-of-day and aiding adjustment to global time zone changes. Thus, performance, which is under the control of the athlete, may be impacted by event time-of-day scheduling in the new time zone. It has previously been shown that individual sport athletes in South Africa tend to be morning-types and carry the PERIOD3 (PER3) Variable Number Tandem Repeat (VNTR) 5-repeat allele, which has been associated with a preference for mornings. The distribution of the PER3 VNTR polymorphism in combination with an individual's preference for mornings or evenings has not yet been described in team sports. Differences in the PER3 VNTR genotype between team and individual sport athletes are expected, given that individual sport athletes may be free to choose the time-of-day at which they train. In contrast, team sport athletes usually train in groups, thus these individuals may not have the flexibility to choose their preferred training times. There are notable inter-individual differences in adjustment to jet-lag after time zone changes. A possible genetic candidate that may be responsible for some of this variation is the PER3 VNTR gene. This gene consist of two alleles corresponding in size to 4-repeats (PER34) or 5-repeats (PER35). Individuals are either homozygous for the 4-repeat allele (PER⁴⁄⁴) or the 5-repeat allele (PER3⁵⁄⁵), while others are heterozygous for the PER3 gene (PER34/5). The PER3 VNTR genotype might explain individual sensitivity to bright light and has been reported to be associated with sleep pressure- an increase in the brain's pressure and need for sleep, following an extended period of awakening. Individuals homozygous for the longer variant of the gene (i.e. PER3⁵⁄⁵) experience a higher sleep pressure during extended wakefulness. The PER3⁵⁄⁵ genotype has been reported to be more sensitive to the alerting and melatonin suppression effects of blue enriched light than the PER⁴⁄⁴ genotype. Aims: Therefore, the aim of Study 1 was to compare the chronotype and PER3 VNTR genotype distribution of South African Super Rugby players to individuals of low physical activity (i.e. those who are physically active ≤2 times per week). The aim of Study 2 was to determine whether PER3 VNTR genotype might contribute to inter-individual variation in the extent to which game involvement and quality of play are affected following trans-meridian travel. Further, the aim of Study 3 was to compare the impact of time zone travel during the 2012 Super Rugby competition in South African players genotyped as PER⁴⁄⁴, PER34/5 and PER3⁵⁄⁵ on the incidence of illnesses and injuries. Lastly, the aim of Study 4 was to compare the extent to which individuals genotyped as PER⁴⁄⁴ or PER3⁵⁄⁵ respond to appropriately-timed blue light exposure in order to resynchronise their circadian rhythm, following simulated eastward travel, based on changes in dim-light melatonin onset and cortisol circadian phases.
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    Sleep and BMI in South African urban and rural, high and low-income preschool children
    (2021-03-23) Rae, Dale E; Tomaz, Simone A; Jones, Rachel A; Hinkley, Trina; Twine, Rhian; Kahn, Kathleen; Norris, Shane A; Draper, Catherine E
    Abstract Background The extent to which income setting or rural and urban environments modify the association between sleep and obesity in young children is unclear. The aims of this cross-sectional observational study were to (i) describe and compare sleep in South African preschool children from rural low-income (RL), urban low-income (UL) and urban high-income (UH) settings; and (ii) test for associations between sleep parameters and body mass index (BMI). Methods Participants were preschoolers (5.2 ± 0.7y, 49.5% boys) from RL (n = 111), UL (n = 65) and UH (n = 22) settings. Height and weight were measured. Sleep, sedentary behaviour and physical activity were assessed using accelerometery. Results UL children had higher BMI z-scores (median: 0.39; interquartile range: − 0.27, 0.99) than the UH (− 0.38; − 0.88, 0.11) and RL (− 0.08; − 0.83, 0.53) children (p = 0.001). The UL children had later bedtimes (p < 0.001) and wake-up times (p < 0.001) and shorter 24 h (p < 0.001) and nocturnal (p < 0.001) sleep durations than the RL and UH children. After adjusting for age, sex, setting, SB and PA, for every hour less sleep obtained (24 h and nocturnal), children were 2.28 (95% CI: 1.28–4.35) and 2.22 (95% CI: 1.27–3.85) more likely, respectively, to belong to a higher BMI z-score quartile. Conclusions Shorter sleep is associated with a higher BMI z-score in South African preschoolers, despite high levels of PA, with UL children appearing to be particularly vulnerable.