Transient sweat response of the human head during cycling
This research aims at quantifying transient spatial gradients in sweat production on a human head while cycling.Six test persons were studied. Each test lasted 30 min while a change in work rate was applied after 5 min (from 80 to 150 W for males and from 50 to 125 W for females). Two conditions were analyzed in this research: warm (28.3 ± 0.1 °C, 38 ± 0.6% RH and 0.1 ± 0.1 m/s air velocity) and standard (16.1° ± 0.2 C, 45% ± 0.6 RH and 2.4 ± 0.2 m/s air velocity). Sweat production of the head was measured as a function of time on the right temple, left temple and forehead. This allowed modelling the dynamics of the sweat production response. Constant steady state sweat production, time delay in sweat production, time constant of sweat production and steady state gain of sweat production were quantified and analyzed.Time constants of sweat production were shorter in the warm condition compared to the standard condition. Mean and SEM time constant of sweat production varied from 561 ± 144 s (frontal region) to 1117 ± 230 s (left temple) and 1080 ± 232 s (right temple) in the warm condition. While, at the standard condition, the time constant of sweat production varied from 873 ± 121 s at the frontal region to 1431 ± 195 s at the left temple and 1727 ± 196 s at the right temple. Additionally, also constant steady state sweat production was 0.4–0.7 mg min−1 cm−2 higher in the warm compared to the standard condition (P < 0.05). However, no differences (P > 0.05) were observed for steady state gain and time delay of sweat production between the standard and warm condition.The results of this research can be used to enhance physiological insight of the sweating process and it can also help to develop sweating thermal manikins that behave more realistically to thermal changes. Knowledge of sweat production might also be valuable when designing active controlled headgear since the reaction time of the actuator should take the dynamics of sweat rate into account as a function of work rate and thermal environmental conditions.Relevance to industryUnderstanding of the dynamic behaviour of sweat production in relation to work rate under different environmental conditions allows the design of model based controllers in headgear that actively minimize sweat production. This could help a user's desire to wear a helmet as well as his ability to concentrate.
Available from: Jean-Marie Aerts
- " 2011 ) and varied spatially with most studies reporting higher sweat rates at the forehead compared to the temple , vertex or rear regions ( Cabanac and Brinnel , 1988 ; Machado - Moreira et al . , 2008 ; Smith and Havenith , 2011 ) , whereas lower sweat rates at the forehead compared to the temple were observed in a study on bicycle helmets ( De Bruyne et al . , 2010 ) . A relative association of local head sweat rate to whole body sweat rate was reported by Smith and Havenith ( 2011 ) with values ranging from 64% to 126% depending on head region and exercise intensity . Using a ventilated helmet - like measuring device , O ' Brien and Cadarette ( 2013 ) reported local head sweating rates amounting "
09/2015; 4(Suppl 1):A71. DOI:10.1186/2046-7648-4-S1-A71
Available from: Toh Yen Pang
- "As a result, helmet usage and design could have a considerable bearing on thermal comfort. Hence, understanding the thermal behaviour of the head is important to form a basis for design and optimization of helmets for thermal comfort and to reduce heat strain to wearers (Bogerd and Brühwiler, 2008; De Bruyne et al., 2010). Many researchers have developed a number of theories and models to analyse and understand thermal comfort (Lotens and Havenith, 1991; Fan and Chen, 2002; Mccullough and Kenney, 2003; O gulata, 2007; Qian and Fan, 2009; Wang et al., 2011). "
[Show abstract] [Hide abstract]
ABSTRACT: The main objective of this study is to establish an approach for measuring the dry and evaporative heat dissipation cricket helmets. A range of cricket helmets has been tested using a sweating manikin within a controlled climatic chamber. The thermal manikin experiments were conducted in two stages, namely the (i) dry test and (ii) wet test. The ambient air temperature for the dry tests was controlled to ∼23 °C, and the mean skin temperatures averaged ∼35 °C. The thermal insulation value measured for the manikin with helmet ensemble ranged from 1.0 to 1.2 clo. The results showed that among the five cricket helmets, the Masuri helmet offered slightly more thermal insulation while the Elite helmet offered the least. However, under the dry laboratory conditions and with minimal air movement (air velocity = 0.08 ± 0.01 ms(-1)), small differences exist between the thermal resistance values for the tested helmets. The wet tests were conducted in an isothermal condition, with an ambient and skin mean temperatures averaged ∼35 °C, the evaporative resistance, Ret, varied between 36 and 60 m(2) Pa W(-1). These large variations in evaporative heat dissipation values are due to the presence of a thick layer of comfort lining in certain helmet designs. This finding suggests that the type and design of padding may influence the rate of evaporative heat dissipation from the head and face; hence the type of material and thickness of the padding is critical for the effectiveness of evaporative heat loss and comfort of the wearer. Issues for further investigations in field trials are discussed.
Applied ergonomics 05/2013; 45(2). DOI:10.1016/j.apergo.2013.04.011 · 2.02 Impact Factor
Available from: Yi-Lang Chen
- "Previous studies have concentrated on the racing bicycle and racing speed and/or efficiency   . Some studies have also focused on biomechanical analyses  , physiological response     , and kinematics , while cycling. Burke  indicated that the primary requirement of a proper interface between the bike and the cyclist is comfort. "
[Show abstract] [Hide abstract]
ABSTRACT: This study attempts to find the optimal trunk flexion (TF) of a recreational cyclist's subjective discomfort rating while cycling. Two hundred and fifty cyclists were sagittally filmed while cycling on a cycle-way, and their subjective body discomforts were rated. The cyclists also responded to a brief questionnaire. Results show that the TF is positively related to the discomfort on neck/shoulders and is contrary to that on the buttocks. The bike owner cyclists’ (n = 144) trunks were more flexed than the bike rental cyclists’ (n = 106), with a difference of about 11°. This study also found that the cyclists may subjectively perceive the minimum discomforts of both the buttocks and neck/shoulders regions when the trunk was nearly flexed to 38°. This finding serves as a reference for ergonomic consideration in bike design to avoid extreme discomfort while cycling.
Journal of the Chinese Institute of Industrial Engineers 12/2012; 29(8). DOI:10.1080/10170669.2012.729762
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.