Background: Currently, and to the best of our knowledge, there is no standardized protocol to measure the effect of low- to moderate-intensity physical exercise on autonomic modulation focused in older people. Aim: Validate a test–retest short-term exercise protocol for measuring the autonomic response through HRV in older people. Methods: A test–retest study design was used. The participants were selected through intentional non-probabilistic sampling. A total of 105 older people (male: 21.9%; female: 78.1%) were recruited from a local community. The assessment protocol evaluated HRV before and immediately after the 2-min step test. It was performed twice on the same day, considering a time of three chronological hours between the two measurements. Results: The posterior distribution of estimated responses in the Bayesian framework suggests moderate to strong evidence favoring a null effect between measurements. In addition, there was moderate to robust agreement between heart rate variability (HRV) indices and assessments, except for low frequency and very low frequency, which showed weak agreement. Conclusions: Our results provide moderate to strong evidence for using HRV to measure cardiac autonomic response to moderate exercise, suggesting that it is sufficiently reliable to show similar results to those shown in this test–retest protocol.

Objective. The study characterized the levels of anxiety and cognitive impairment of older people in the Chilean city of Punta Arenas, exploring possible correlations between both phenomena. Methods. With a descriptive pilot design, 72 older people (60-87 years) residing in Punta Arenas were evaluated using the Beck Anxiety Inventory (BAI) and Montreal Cognitive Assessment (MoCA) tests to measure anxiety and cognitive impairment, respectively. Results. Women were found to have significantly higher BAI scores than men (9,0 vs 3,5; p = 0,025), without significant differences in MoCA by sex. BAI and MoCA total scores showed an inverse correlation. Those over 70 years of age had a greater probability of altered scores in BAI, and a non-significant trend in MoCA (OR: 2.43; p = 0.066). Men showed higher rates of cognitive deterioration than women, although without statistical significance. Conclusion. Those over 70 years of age showed a greater probability of altered anxiety and a non-significant trend toward greater cognitive deterioration. The results underscore the need for specific interventions to improve mental and cognitive health in this vulnerable population.

Objetivo: Investigar el impacto del dolor muscular de aparición tardía inducido por ejercicios excéntricos (DOMS, por sus siglas en inglés) sobre la actividad autonómica cardíaca en atletas adolescentes. Métodos: Se llevó a cabo un diseño preexperimental de un solo grupo con preprueba y postprueba en quince atletas adolescentes competitivos, y se evaluó el efecto de DOMS en la actividad autonómica cardíaca, controlando por composición corporal y los factores de ansiedad estado/rasgo. Se aplicó un protocolo de ejercicio excéntrico a los músculos flexores del codo para inducir DOMS. Luego, se comparó la variabilidad de la frecuencia cardíaca antes y dos días después de la inducción de DOMS, tanto en condiciones de reposo como durante movimientos resistidos del miembro con dolor, utilizando la prueba t para muestras pareadas. Además, se midió la composición corporal y el Inventario de Ansiedad Estado-Rasgo (STAI, por sus siglas en inglés). Resultados: El análisis reveló un efecto significativo de DOMS en la respuesta autonómica cardíaca en el dominio de tiempo en raíz cuadrada de las diferencias sucesivas (RMSSD) (MD = -5.58, IC del 95%[-9.36, -1.8], t(14) = -3.2, p = 0.007) y desviación estándar de los intervalos normales a normales (SDNN) (MD = -9.43, IC del 95%[-15.47, -3.39], t(13) = -3.4, p = 0.005), así como en los índices autonómicos del sistema nervioso simpático (SNS, por sus siglas en inglés) (MD = 0.68, IC del 95%[0.07, 1.29], t(14) = 2.4, p = 0.031) e Índice de Estrés (SI) (MD = 2.72, IC del 95%[0.67, 4.77], t(14) = 2.8, p = 0.013) en condiciones de ejercicio. Conclusiones: El DOMS modifica la actividad autonómica cardíaca en comparación con condiciones de control durante el dolor evocado mecánicamente, pero no en reposo. Este estudio destaca la importancia de considerar la presencia de DOMS cuando se utiliza la VFC en atletas adolescentes para fines de entrenamiento, clínicos o de investigación. Palabras clave: Deportes, Dolor agudo, Sistema nervioso autónomo, Hiperalgesia mecánica, Daño muscular Objective: To investigate the impact of eccentric-induced delayed-onset muscle soreness (DOMS) on cardiac autonomic activity in adolescent athletes. Methods: A pre-experimental one-group pre-test/post-test design was carried out on fifteen competitive adolescent athletes, and the effect of DOMS on cardiac autonomic activity was assessed while controlling for body composition and anxious state/trait factors. An eccentric exercise protocol was applied to the elbow’s flexor muscles to induce DOMS. Then, heart rate variability was compared before and two days after DOMS induction under resting and resisted movement conditions of the painful limb, using a t-test for paired samples. The body composition and the State-Trait Anxiety Inventory (STAI) were also measured. Results: The analysis revealed a significant effect of DOMS on autonomic response in time domain measures of root mean square of successive differences (RMSSD) (MD = -5.58, 95%CI[-9.36, -1.8], t(14) = -3.2, p = 0.007) and standard deviation of normal-to-normal intervals (SDNN) (MD = -9.43, 95%CI[-15.47, -3.39], t(13) = -3.4, p = 0.005), as well as on sympathetic nervous system (SNS) autonomic indices (MD = 0.68, 95%CI[0.07, 1.29], t(14) = 2.4, p = 0.031) and Stress index (SI) (MD = 2.72, 95%CI[0.67, 4.77], t(14) = 2.8, p = 0.013) under exercise conditions. Conclusions: DOMS changes cardiac autonomic activity compared to control conditions during mechanically evoked pain but not at rest. This study highlights the importance of considering the presence of DOMS when HRV is used in adolescent athletes for training, clinical, or research purposes. Keywords: Sports, Acute pain, Autonomic nervous system, Mechanical hyperalgesia, Muscle damage

Introduction. Non-cancer chronic pain is a significant global public health issue, particularly within specific populations, and is shaped by a complex interplay of biological, psychological, and social factors. University students face unique lifestyle challenges that may increase their vulnerability to chronic pain and its associated functional impairments. However, this population remains underrepresented in research, leaving important gaps in our understanding. Aim. This study explored the relationship between non-cancer chronic pain, its presence, characteristics, and functional impact, and biopsychosocial factors linked to university life, including physical activity, sleep quality, and mental health. Methods. A cross-sectional observational study was conducted among 157 full-time students from two universities in Chile's Austral Macrozone. Data were collected using online questionnaires assessing pain, sociodemographic information, sleep, chronotype, physical activity, and mental health. Statistical analyses were carried out using Bayesian modeling. Results. Females had a higher risk of chronic pain (exp(β) = 6.96), with greater intensity and functional impact. Engineering students were at higher risk compared to health sciences (exp(β) = 7.69), and health sciences compared to social sciences (exp(β) = 3.89). Moderate physical activity showed a protective effect against pain (exp(β) = 2.95). Matutine chronotypes and better sleep quality were linked to reduced functional impact and pain frequency. Conclusion. Biopsychosocial variables —including sociodemographic characteristics, physical activity levels, mental health, and sleep quality— were significantly associated with the presence, frequency, and functional consequences of chronic pain among Chilean university students. These findings highlight the importance of addressing such factors in the development of preventive and management strategies targeting chronic pain in this population.

Introduction. Aging brings physiological, psychological, and social changes, such as stress-coping strategies and physical fitness. Seasonal sensitivity, which includes mood and behavioral shifts in response to seasonal changes, is particularly influential. This study examines the relationships between seasonal sensitivity, perceived stress, and physical performance in older adults living in high southern latitudes. Methodology. An analytical cross-sectional study was conducted with 77 older adults (60 females and 17 males, aged 60 to 89). Seasonal sensitivity was measured using the Seasonal Pattern Assessment Questionnaire, perceived stress with the Perceived Stress Scale, and physical performance with the Short Physical Performance Battery. Results. Increased seasonal sensitivity was associated with higher perceived stress, especially among individuals with "Winter Blues" (β = -0.67, 95% CI [-1.21, -0.13], p < .01) compared with those with typical sensitivity. In contrast, those diagnosed with Seasonal Affective Disorder reported lower stress levels and showed better adaptation to seasonal changes. Physical performance, notably in the sit-to-stand task, was more closely linked to typical sensitivity scores than to extremes of seasonal sensitivity. Discussion. These findings highlight the interplay between seasonal sensitivity, stress, and physical performance. Integrated psychosocial and physical interventions may optimize well-being among older adults in high-latitude settings. Conclusions. Seasonal sensitivity is significantly associated with perceived stress and physical performance among older adults in high southern latitudes. Individuals experiencing "Winter Blues" show elevated stress levels compared with those with typical sensitivity, whereas those with Seasonal Affective Disorder display better symptom management.