Physiologia, Volume 2, Issue 4 (December 2022) – 6 articles

This systematic review aims to summarize the effects of wearing different types of wetsuits and swimsuits in front crawl swimming performance and physiological- and biomechanical-related variables. The Web of Science, PubMed, Scopus and the Proceedings of the International Symposium on Biomechanics and Medicine in Swimming databases were searched from inception to 25th March 2022. From the 1398 studies initially found, 26 studies were included in the review. The quality assessment and inter-rater reliability between researchers were conducted. The full body was the most studied wetsuit, with its use allowing 3.2–12.9% velocity increments in distances ranging from 25 to 1500 m, in incremental tests, in 5 and 30 min continuous swimming and in open water events. The sleeveless long vs. the full-body wetsuit led to a 400–800 m performance enhancement. Higher stroke rate, stroke length and stroke index were observed while using three different covered body part wetsuits vs. a regular swimsuit, with a lower energy cost being observed when swimming with the full-body wetsuit compared to a swimsuit. These findings provide useful information for coaches, swimmers and triathletes about the full-body and sleeveless long/short wetsuit use, since these three wetsuits allow improving swimming performance in different distances in diverse aquatic environments. Full article

Drought is an important abiotic stress factor limiting crop productivity worldwide and its impact is increasing with climate change. Regardless of the plant growth period, drought has a deadly and yield-reducing effect on the plant at every stage of development. As with many environmental stressors, drought-exposed plants trigger a series of molecular, biochemical, and physiological responses to overcome the effect of drought stress. Currently, researchers are trying to determine the complex functioning of drought stress response in plants with different approaches. Plants are more sensitive to drought stress during certain critical stages like germination, seedling formation, flowering, fertilization, and grain formation periods. Plants have high success in reducing the effects of drought stress in vegetative development periods with the activity of tolerance mechanisms. On the other hand, drought stress during the generative period can cause irreversible losses in yield. This review focuses on the progression of molecular, biochemical, and physiological mechanisms involved in the drought stress tolerance in plants and the responses of field crops to drought stress at different development stages. Full article

Maintenance of skeletal muscle mass and function is critical to health and wellbeing throughout the lifespan. However, disuse through reduced physical activity (e.g., sedentarism), immobilisation, bed rest or microgravity has significant adverse effects on skeletal muscle health. Conversely, resistance exercise training (RET) induces positive muscle mass and strength adaptations. Several studies have employed microarray technology to understand the transcriptional basis of muscle atrophy and hypertrophy after disuse and RET, respectively, to devise fully effective therapeutic interventions. More recently, rapidly falling costs have seen RNA-sequencing (RNA-seq) increasingly applied in exploring muscle adaptations to RET and disuse. The aim of this review is to summarise the transcriptional responses to RET or disuse measured via RNA-seq in young and older adults. We also highlight analytical considerations to maximise the utility of RNA-seq in the context of skeletal muscle research. The limited number of muscle transcriptional signatures obtained thus far with RNA-seq are generally consistent with those obtained with microarrays. However, RNA-seq may provide additional molecular insight, particularly when combined with data-driven approaches such as correlation network analyses. In this context, it is essential to consider the most appropriate study design parameters as well as bioinformatic and statistical approaches. This will facilitate the use of RNA-seq to better understand the transcriptional regulators of skeletal muscle plasticity in response to increased or decreased use. Full article

Delayed recovery of the core body temperature after exercise adversely affects physiological functions, and the effects of ingesting lower-temperature ice slurry on post-exercise recovery remain unclear. We investigated the effects of ingesting −2 °C ice slurry on physiological recovery after field-based rugby union training. Fifteen university rugby union players participated in our randomized controlled study. The players participated in the training for 60 min in a hot outdoor environment (wet-bulb globe temperature, 30.5 °C). Physiological responses were measured during a physical performance test performed after the players ingested either −2 °C-ice slurry (ICE, N = 7) at 5 g/kg body mass or a 30 °C-fluid (CON, N = 8) during the 15 min recovery period after the training. Tympanic temperatures and heart rates were measured as the physiological indices, as well as heat storage. The ICE group showed significantly decreased tympanic temperatures and heart rates (p < 0.05) during the recovery period and increased heat storage (p < 0.05) but did not show improvement of physiological indices during the performance test compared to the CON group. These results suggest that ingestion of −2 °C ice slurry in even lower amounts than those previously reported is useful for physiological recovery after training in hot outdoor environments. Full article

In the present study, we examined the light quality and photoperiod-dependent physiological performance of Mimosa pudica. Plants were grown in pots under white, blue, green and red-light compositions under 12 h per day (12/12 h) and 24 h per day (24/0 h) for 12 days. After 12 days, the physiological parameters’ morphology, fresh weight, chlorophyll fluorescence and biochemical analyses, which include antioxidants, lipid peroxidation, pigment content and carbohydrate content were also measured. Necrosis was found in red, blue and green light and the plant was senesced at the end of the experiment. The blue 24-h light period showed the highest pigment and antioxidant content, whereas the lowest was observed in green light conditions. The OJIP curve was complete in white light, hence it was not completely formed in red, blue and green light. The phenomenological parameters also fluctuated in different light conditions. Photosynthesis ultimately results in starch content, which was highest in blue light and lowest in red light. Different monochromatic light qualities inhibited plant growth by reducing the activity of photosynthetic apparatus in plants. White light was more effective in driving photosynthesis and promoting the plant growth, while green and red light showed a suppressive effect on plants’ growth. The 24 h photoperiod was also accompanied by various spectra to reduce the plants’ growth. The results clearly indicate that the photoperiod and light spectrum must be considered before growing plants in a greenhouse. Full article

(1) Background: Maximal fat oxidation (MFO), its associated exercise intensity (Fatmax) and the cross-over point (COP) are known indirect calorimetry-based diagnostics for whole-body metabolic health and exercise. However, large inter- and intra-individual variability in determining their corresponding intensity makes their use inconsistent, whether the intensity is based on power output or oxygen uptake. Blood lactate concentration (BLC) has often reflected a range in MFO and COP, which may offer another non-indirect calorimetry dimension based on the near equilibrium between lactate and pyruvate at the molecular level, which biochemically determines an interchange between lactate and relative rate of carbohydrate (relCHO) and relative rate of fat utilization (relFAO). This paper proposes a new testing approach describing relCHO as a function of BLC, with an individualized half-maximal activation constant of relCHO (kel), to explain and predict the variability in MFO, Fatmax and COP. (2) Methods: Following ethical approval, twenty-one healthy males participated in the incremental cardiorespiratory maximal test, and capillary BLC was measured. Indirect calorimetry relCHO and relFAO were calculated, and a constant kel that reflected 50% of CHO saturation level was estimated as a sigmoid function of BLC (mmol·L⁻¹): relCHO = 100/(1 + kel/BLC²). (3) Results: 86% of relCHO variability was explained by BLC levels. The individualized kel estimations, which were 1.82 ± 0.95 (min/max 0.54/4.4) (mmol·L⁻¹)² independently explained 55% MFO and 44% of COP variabilities. Multiple regression analysis resulted in kel as the highest independent predictor of Fatmax (adjusted r-square = 22.3%, p < 0.05), whilst classic intensity-based predictors (peak power, maximal oxygen uptake, fixed BLC at 4 mmol·L⁻¹) were not significant predictors. (4) Conclusions: The BLC-relCHO model, with its predictor kel explains the inter- and intra-individual variability in MFO, its exercise intensity Fatmax and power outs at COP through dynamic changes in BLC, fat and carbohydrates regardless of the intensity at which exercise takes place. kel capability as a predictor of MFO, Fatmax and COP independently of their associated intensities provides a new diagnostic tool in physiological exercise testing for health and exercise performance. Full article