PERIOD3 variable number tandem repeat genotype associations with performance, injury, illness and re-entrainment

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

Diurnal preference and sports performance : a subjective and genetic view

[T]he purpose of this study was to describe the distribution of morning- or evening-preferring individuals (measured using the Horne-Östberg morningness-eveningness personality questionnaire) and PER3 VNTR polymorphism (from genomic DNA products extracted from human buccal cell samples amplified and digested with NcoI) within male Caucasian, trained cyclists (CYC, n=138), Ironman triathletes (IM, n=301) and an active, but non-competitive control population of Caucasian males (CON, n=120). In addition, performance was assessed in trained cyclists strongly preferring mornings or evenings at various times of day

Risk factors associated with acute respiratory illnesses in athletes : a systematic review by a subgroup of the IOC consensus on 'acute respiratory illness in the athlete'

OBJECTIVE : To review risk factors associated with acute respiratory illness (ARill) in athletes, including non-infectious ARill and suspected or confirmed acute respiratory infections (ARinf). DESIGN : Systematic review. DATA SOURCES : Electronic databases: PubMed-Medline, EbscoHost and Web of Science. ELIGIBILITY CRITERIA : Original research articles published between January 1990 and July 2020 in English were searched for prospective and retrospective full text studies that reported quantitative data on risk factors associated with ARill/ARinf in athletes, at any level of performance (elite/non-elite), aged 15–65 years. RESULTS : 48 studies (n=19 390 athletes) were included in the study. Risk factors associated with ARill/ARinf were: increased training monotony, endurance training programmes, lack of tapering, training during winter or at altitude, international travel and vitamin D deficits. Low tear-(SIgA) and salivary-(IgA) were immune biomarkers associated with ARill/ARinf. CONCLUSIONS : Modifiable training and environmental risk factors could be considered by sports coaches and athletes to reduce the risk of ARill/ARinf. Clinicians working with athletes can consider assessing and treating specific nutritional deficiencies such as vitamin D. More research regarding the role and clinical application of measuring immune biomarkers in athletes at high risk of ARill/ARinf is warranted.http://bjsm.bmj.comhj2023Sports Medicin

Incidence of acute respiratory illnesses in athletes: a systematic review and meta-analysis by a subgroup of the IOC consensus on 'acute respiratory illness in the athlete'

OBJECTIVE : To determine the incidence of acute respiratory illness (ARill) in athletes and by method of diagnosis, anatomical classification, ages, levels of performance and seasons. DESIGN : Systematic review and meta-analysis. DATA SOURCES : Electronic databases: PubMed-Medline, EbscoHost and Web of Science. ELIGIBILITY CRITERIA : Original research articles published between January 1990 and July 2020 in English reporting the incidence of ARill in athletes, at any level of performance (elite/non-elite), aged 15–65 years. RESULTS : Across all 124 studies (n=1 28 360 athletes), the incidence of ARill, estimated by dividing the number of cases by the total number of athlete days, was 4.7 (95% CI 3.9 to 5.7) per 1000 athlete days. In studies reporting acute respiratory infections (ARinf; suspected and confirmed) the incidence was 4.9 (95% CI 4.0 to 6.0), which was similar in studies reporting undiagnosed ARill (3.7; 95% CI 2.1 to 6.7). Incidences of 5.9 (95% CI 4.8 to 7.2) and 2.8 (95% CI 1.8 to 4.5) were found for studies reporting upper ARinf and general ARinf (upper or lower), respectively. The incidence of ARinf was similar across the different methods to diagnose ARinf. A higher incidence of ARinf was found in non-elite (8.7; 95% CI 6.1 to 12.5) vs elite athletes (4.2; 95% CI 3.3 to 5.3). SUMMARY/CONCLUSIONS : These findings suggest: (1) the incidence of ARill equates to approximately 4.7 per athlete per year; (2) the incidence of upper ARinf was significantly higher than general (upper/lower) ARinf; (3) elite athletes have a lower incidence of ARinf than non-elite athletes; (4) if pathogen identification is not available, physicians can confidently use validated questionnaires and checklists to screen athletes for suspected ARinf. For future studies, we recommend that a clear diagnosis of ARill is reported. PROSPERO registration number CRD42020160472.https://bjsm.bmj.comhj2023Sports Medicin

“It gives me a wake up call”—It is time to implement athlete health monitoring within the Para sport context

ObjectivesThe aim of this study was to explore elite Para athletes' and coaches' perceptions of experiences of athlete health monitoring.Materials and MethodsThis study used a qualitative design, applying a phenomenographical approach. Thirteen athletes and six coaches from two different socioeconomic contexts (the Swedish and South African Paralympic programs) participated. Data were collected through individual interviews focusing on athletes' and coaches' perceptions of experiences of athlete health monitoring within Para sport.ResultsThree main themes were revealed: (i) the benefits of athlete health monitoring, (ii) the importance of implementation and adaptation of athlete health monitoring in the real-world sports context, and (iii) barriers of athlete health monitoring. The perceptions were that regular monitoring can detect injuries early and thereby prevent them from progressing. Several participants highlighted the importance of monitoring factors beyond injury and illness, such as Para sport-specific health issues. Athletes' experiences were that they started to reflect on their own health, which was interpreted as improvement in health literacy. Another perception was that athlete health monitoring only is conducted within the research context and that athletes are not followed up. The perception was that it is the sports federations' responsibility to monitor and provide support when needed. Lastly, data revealed differences in the possibilities of conducting monitoring, which was related to both socioeconomic factors and Para sport.ConclusionCoaches and athletes see health monitoring as valuable and important in enhancing athlete health. However, to maximize the impact, the monitoring structure should be specific to the context and provide multidisciplinary support when needed

Presenting features of female collegiate sports-related concussion in South Africa: a descriptive analysis

Background: Sports-related concussion (SRC) is an injury with important implications, especially in collision and contact sports, and has a high symptom burden. Student athletes face particular psychosocial challenges, especially female students with pre-existing anxiety/depression are at increased risk for SRC, and have a higher symptom burden before and after injury. Objectives: Describing female SRC presenting features at a collegiate campus-based sports medicine service; examining the association of prior concussion history (PCONC) and pre- existing anxiety/depression (PMHDx) with SRC. Methods: A retrospective cohort and statistical analysis (including corrected effect sizes) of Sport Concussion Assessment Tool (versions 3/5) data (Step 1: PCONC and PMHDx history; Step 2: symptom evaluation) of collegiate female athletes with SRC between 2012 and 2018. Results: Forty females with SRC were identified (age 23 ± 3). The five most frequent symptoms were headache (n = 34; 85%), feeling slowed down (n = 33; 83%), pressure in head (n = 33; 83%), don't feel right (n = 32; 80%) and fatigue/low-energy (n = 32; 80%). These five symptoms also had the highest self-rated severity (median (IQR): headache (3 (2-4)), feeling slowed down (3 (1-4)), fatigue/low-energy (3 (1-5)), don't feel right (3 (1-4)) and pressure in head (3 (2-4)). PMHDx (n = 8; 62.9 vs 38.6; p = 0.0192; Hedges' gs = 0.95; large ES), and not PCONC (n = 13; 51.0 vs 39.8; p = 0.2183; Hedges' gs = 0.48; small ES) was associated with increased mean total symptom severity. Conclusion: Headache, feeling slowed down, pressure in head, don't feel right and fatigue/low-energy had the highest symptom burden. Total symptom severity was no different in those with and without PCONC, but significantly higher in those with PMHDx