In this study, we investigated the activation of the prefrontal cortex (PFC) on both sides during the maximum hand grip task (MHG task). Seven healthy right-handed male subjects participated in this study. With the functional Near infrared spectroscopy (NIRS) probe placed on the PFC, the subjects repeated the MHG task for 3 seconds 50 times. The oxygenation value in the contralateral prefrontal cortex (Contra-PFC) and the ipsilateral prefrontal cortex (Ipsi-PFC) increased significantly (p<0.01) compared to the baseline value from the start of the MHG task, then the oxygenation value of the Contra-PFC gradually decreased. On the other hand, the oxygenation value of the Ipsi-PFC was significantly increased compared to the baseline value until the task end. The maximum hand grip strength (MHG strength) and the integrated electromyograph (iEMG) decreased significantly from the start of the task (p<0.05). After that, while the significant activation of the Ipsi-PFC was continuing, the values of iEMG and MHG strength were not further reduced until the task was completed. In conclusion, as fatigue accumulates during tasks, the Ipsi-PFC may become more active than the Contra-PFC to prevent further degradation of the muscle function.

Kolkata is one of the metropolitan cities of the world where bus commuter density is significantly high. A large number of bus drivers are engaged in operating the intra-city and inter-city trips. They are exposed to different types of hazards but there is dearth of data. This study is aimed to evaluate the exposure on musculoskeletal problems of bus drivers. One hundred forty bus drivers in different bus routes in Kolkata participated in the study. They were divided in Group 1 and Group 2. A modified Nordic questionnaire and the Oswestry Low Back Pain Disability Questionnaire were administered on the bus drivers. Finally discomfort levels of individual working postures were calculated by the use of the risk level and the Body Part Discomfort scale. BMI values indicated the many bus drivers were deviated from a ‘normal healthy’ category and 92% had abdominal obesity due to improper food habits. Main affected body parts were the lower back, shoulder, lower back and calf. Several factors were responsible for the prevalence of physiological and musculoskeletal problems such as high job demands, repetitive and awkward postures, vibration and inadequate rest-break opportunities. Abdominal obesity, improper BMI and years of exposure were the co-morbid factors for musculoskeletal disorders of the drivers.

Forty young Muslim untrained male subjects (mean age: 22.67±1.75 years, mean height: 165.72 ±7.72 cm) participating in Ramadan intermittent fasting (RIF) and forty non-fasting counterparts (mean age: 23.05±1.43 years, mean height: 165.22±4.29 cm) from different parts of Kolkata, India were recruited in the study to evaluate the effects of RIF on different components of body composition. One-way repeated measure ANOVA depicted significant difference in the studied parameters in the experimental group (EG) whereas the control group (CG) showed insignificant difference in the studied parameters. Significant difference was also noted when the change of body composition in terms of skinfolds, body density, percentage of body fat (%Fat), total fat, lean body mass (LBM) and %LBM was compared between CG and EG. It can be concluded from the present investigation that RIF adversely affected the body composition in fasting individuals although body mass was not influenced by RIF in the studied population.

　The ratio of the low frequency (LF) and high frequency (HF) bands of heart rate variability (LF/HF) was used to evaluate the balance between sympathetic and parasympathetic nervous activities, and HF was used for evaluating the parasympathetic nervous activities. In the present study, we set two conditions using two types of gummy candy (hard: gelatin 11%, soft: gelatin 6%). In the hard condition, the LF/HF was significantly higher during the chewing period (gummy) than the period before the chewing (pre-gummy) (p<0.0001). Furthermore, the LF/HF was significantly lower during the period from just after chewing to 5 minutes after chewing (post-gummy 1) than in the pre-gummy period (p<0.05). In addition, the LF/HF ratio was significantly lower during the period from 5 minutes to 10 minutes after chewing (post-gummy 2) than in the pre-gummy period (p<0.05) in the hard-gummy condition. In the soft condition as the control, the LF/HF ratio was also significantly higher during the gummy chewing than in the pre-gummy (p<0.0001). However, during the post-gummy 1 and post-gummy 2, the LF/HF was not significantly different from that observed in the pre-gummy (p>0.05, respectively). On the other hand, there was no significant changes in HF and heart rate throughout the testing. The results demonstrate that the hardness of food during chewing exercise has an influence on autonomic nervous activity after chewing.