Changes in cortisol awakening responses (CAR) in menopausal women through short-term marine healing retreat program with specific factors affecting each CAR index.

Recent studies have reported that the cortisol awakening response (CAR) is associated with various health risks. The different indices used to represent the CAR include the average cortisol levels in the morning immediately after waking (AVE); the total area under the curve of cortisol levels with respect to ground (AUCg); and the area under the curve of cortisol levels with respect to increase (AUCi). However, it is unclear which physiological phenomenon each index reflects. This study investigated the factors, such as stress, circadian rhythm, sleep, and obesity, affecting the CAR through a marine retreat-based healing program in which the anticipated stress of the participants could be controlled to some degree. Fifty-one menopausal women in their 50s and 60s were included, who performed beach yoga and Nordic walking for four days at an uncontaminated beach. The baseline CAR indices showed that the AVE and AUCg were significantly higher in the high sleep efficiency group than in the low sleep efficiency group. However, the AUCi decreased substantially with increasing age. The changes in the AVE, AUCg, and AUCi were calculated through the program, and it was found that the AVE and AUCg increased significantly more in the obese group than in the normal and overweight groups. The obese group also showed significantly decreased serum triglyceride and BDNF (brain-derived neurotrophic factor) levels compared to the low BMI group. Thus, it was confirmed that AVE and AUCg reflected physiological phenomena affected by factors such as sleep efficiency and obesity, whereas the AUCi was affected by factors such as age. In addition, the marine retreat program can improve the low levels of CAR associated with obesity and aging.

Effect of the Marine Exercise Retreat Program on Thyroid-Related Hormones in Middle-Aged Euthyroid Women.

This study aimed to investigate the effects of a marine exercise retreat program on thyroid-related hormone levels. A total of 62 middle-aged euthyroid women participated in a 6-day marine exercise retreat program. Using thyroid-stimulating hormone (TSH) and free thyroxine (fT4) hormone levels, the participants were divided into high and low-hormone-level groups. Despite decreased TSH and fT4 levels after the program, the factors influencing changes in each group were different. TSH levels were influenced by changes in the normalized low frequency (nLF) of heart rate variability and carbon monoxide (CO) from all the participants, and changes in body fat percentage, nLF, and nitrogen dioxide (NO2) exposure level in the high TSH group. fT4 levels were influenced by changes in body mass index (BMI), NO2 exposure, and particulate matter diameter of 10 µm or less (PM10) exposure in all participants. Changes in BMI and CO exposure influenced the low fT4 group. Lastly, changes in the exercise stress test affected the high fT4 group. Thus, the marine exercise retreat program affected euthyroid thyroid-related hormone levels, and influencing factors differ depending on the initial value of the hormone.

Reduced branched-chain aminotransferase activity alleviates metabolic vulnerability caused by dim light exposure at night in Drosophila.

The rhythmic pattern of biological processes controlled by light over 24 h is termed the circadian rhythm. Disturbance of circadian rhythm due to exposure to light at night (LAN) disrupts the sleep-wake cycle and can promote cardiovascular disease, diabetes, cancer, and metabolic disorders in humans. We studied how dim LAN affects the circadian rhythm and metabolism using male Drosophila. Wild-type flies exposed to the dim light of 10 lux at night displayed altered 24 h sleep-wake behavior and expression patterns of circadian rhythm genes. In addition, the flies became more vulnerable to metabolic stress, such as starvation. Whole-body metabolite analysis revealed decreased amounts of branched-chain amino acids (BCAAs), such as isoleucine and valine. The dim light exposure also increased the expression of branched-chain amino acid aminotransferase (BCAT) and branched-chain α-keto acid dehydrogenase (BCKDC) enzyme complexes that regulate the metabolism of BCAAs. Flies with the Bcat heterozygous mutation were not vulnerable to starvation stress, even when exposed to dim LAN, and hemolymph BCAA levels did not decrease in these flies. Furthermore, the vulnerability to starvation stress was also suppressed when the Bcat expression level was reduced in the whole body, neurons, or fat body during adulthood using conditional GAL4 and RNA interference. Finally, the metabolic vulnerability was reversed when BCAAs were fed to wild-type flies exposed to LAN. Thus, short-term dim light exposure at night affects the expression of circadian genes and BCAA metabolism in Drosophila, implying a novel function of BCAAs in suppressing metabolic stress caused by disrupted circadian rhythm.

Prenatal hyperbaric normoxia treatment improves healthspan and regulates chitin metabolic genes in Drosophila melanogaster.

Aging is a universal, irreversible process accompanied by physiological declines that culminate in death. Rapid progress in gerontology research has revealed that aging can be slowed through mild stress-induced hormesis. We previously reported that hyperbaric normoxia (HN, 2 atm absolute pressure with 10% O2) induces a cytoprotective response in vitro by regulating fibronectin. In the present study, we investigated the hormetic effects of prenatal HN exposure on Drosophila healthspan related to molecular defense mechanisms. HN exposure had no disruptive effect on developmental rate or adult body weight. However, lifespan was clearly enhanced, as was resistance to oxidative and heat stress. In addition, levels of reactive oxygen species were significantly decreased and motor performance was increased. HN stress has been shown to trigger molecular changes in the heat shock response and ROS scavenging system, including hsp70, catalase, glutathione synthase, and MnSOD. Furthermore, to determine the hormetic mechanism underlying these phenotypic and molecular changes, we performed a genome-wide profiling in HN-exposed and control flies. Genes encoding chitin metabolism were highly up-regulated, which could possibly serve to scavenge free radicals. These results identify prenatal HN exposure as a potential hormetic factor that may improve longevity and healthspan by enhancing defense mechanisms in Drosophila.