| 1. |
- Alametsä, Jarmo, et al.
(author)
-
Age-related circulatory responses to whole body cooling: observations by ballistocardiographic EMFi sensors
- 2014
-
In: Proceedings of Ambience 14&10i3m : Scientific Conference for Smart and Functional Textiles, Well-Being, Thermal Comfort in Clothing, Design, Thermal Manikins and Modellin, 7-9 September 2014, Tampere, Finland - Scientific Conference for Smart and Functional Textiles, Well-Being, Thermal Comfort in Clothing, Design, Thermal Manikins and Modellin, 7-9 September 2014, Tampere, Finland. - 2342-4540. - 9789521532696 ; 1
-
Conference paper (peer-reviewed)abstract
- The purpose was to study age related changes in circulatory system via Ballistocardiography (BCG) by utilizing Electromechanical Film (EMFi) sensors by gradually changing the ambient temperature from a thermoneutral area to cold direction. ECG and BCG were recorded from a young person (23 years) and from an older person (78 years), both males. During the tests, brachium blood pressure (BP) and pulse signals were recorded from neck and ankle (with EMFi sensor strips). Thermal camera images were taken in order to find out temperature changes in whole body and limbs. Temporal durations and amplitudes of seat BCG:s components (systolic and diastolic) as well as from pulse signals from neck and ankle were calculated. Aortic pulse wave velocity (PWV) was obtained by utilizing the time between ECG’s R wave and maximum value of the ankle pulse signal. In both persons, the ankle pulse amplitude decreased when propagating to cold direction and increased in young person when returning to warmer ambient temperature. With young and old BCG:s systolic and diastolic temporal complexes remained stable, but systolic amplitudes increased in the older person (AHI 1.02 – 2.87, AIJ 0.7 – 2.66) as well as diastolic amplitudes (old; AKL 0.47 – 2.37). In the older person, PWV increased when moving to colder side. BP increased with a young person (from 95/64 to 132/75 mmHg), and with older person (from 125/68 to 176/101 mmHg) having a prominent rise in diastolic values during the cooling. The neck pulse wave amplitude AOP rise was modest with the younger person and had variation with the older person. Older person had also more intensive shivering compared to younger one. With the older person, the limbs stayed cold in thermal images when returning from cold to thermoneutral area. The present preliminary observations indicated clear age-related differences in the circulatory response to a mild whole-body thermal challenge.
|
|
| 2. |
- Alametsä, Jarmo, et al.
(author)
-
Age‐related circulatory responses to whole body cooling: observations by heart rate variability
- 2015
-
In: Finnish Journal of eHealth and eWelfare. - 1798-0798. ; 7:2-3, s. 57-64
-
Journal article (peer-reviewed)abstract
- The purpose was to study potential age ‐ related changes in the circulatory system via heart rate variability (HRV) by gradually lowering ambient temperature (0.2°C/min) from thermoneutral (32 C°) towards cold (18 C°). ECG was recorded from a young (31 years) and from an older subject (78 years), both males. During the tests, brachium blood pressure (BP) was recorded. During the cooling, BP increased in both subjects (young from 95/69 to 132/75 mmHg, old from 125/68 to 176/101 mmHg), the latter exhibiting a prominent rise in diastolic values after cooling. HRV parameters increased in both subjects during the cold exposure being modest in the younger subject as compared to the older one. Also, recovery from the cold in terms of HRV was faster in the younger subject. The present preliminary observations indicate that older age is coupled with altered HRV response to a mild whole‐body skin cooling.
|
|
| 3. |
- Arias, Silvia, et al.
(author)
-
An experiment on ascending evacuation on a long, stationary escalator
- 2016
-
In: Interflam 2016.
-
Conference paper (other academic/artistic)abstract
- Ascending evacuation is becoming more relevant with underground stations reaching increasing depths. Therefore there is need for better understanding of the effects of physical exertion during evacuation. An experiment was conducted in a 61 m long, stationary escalator in Stockholm (Sweden) in order to obtain data on walking speeds, resting and behavior, which consisted on measuring the walking speed and gathering data about the perceived exertion of test participants walking up the escalator. The walking speeds of 29 single individuals and a group of 21 individuals were obtained. The results showed that people decrease their walking speed with the height, and some of them need to take breaks along the climb. No clear influence of background participants’ variables was found on the results. In the group experiment, the slower people had an impact on the walking speed of others due to the reduced space between them at the beginning of the climb. However, the slower participants gradually move to the right hand of the escalator to allow overtaking on the left hand side, and the faster ones could move at their preferred speed. This behavior is similar that observed during regular use of escalators.
|
|
| 4. |
- Delin, Mattias, et al.
(author)
-
Ascending evacuation - Walking speed in stairs as a function of height
- 2015
-
In: Human Behaviour in fire : 6th International Symposium - 6th International Symposium. - 9780993393303 ; , s. 155-160
-
Conference paper (peer-reviewed)abstract
- During ascending evacuation in long stairs, there is reason to believe that factors such as fatigue, and change in human behaviour will influence the possibility of satisfactory evacuation and affect the ascending walking speed. Based on these assumption, a 2-year research project was initiated at Lund University. This paper gives a brief description of the project and highlight some initial findings according ascending walking speed and effects of fatigue.
|
|
| 5. |
- Delin, Mattias, et al.
(author)
-
Ascending stair evacuation : walking speed as a function of height
- 2017
-
In: Fire and Materials. - : Wiley. - 0308-0501 .- 1099-1018. ; 41:5, s. 514-534
-
Journal article (peer-reviewed)abstract
- There is reason to believe that factors such as physical exertion and behavioural changes will influence the ascending walking speed and ultimately the possibility of satisfactory evacuation. To study these effects, a 2-year research project was initiated with the focus on effects of physical exertion on walking speeds, physiological performance and behaviours during long ascending evacuations. Two sets of experiments on human performance during ascending long stairs, with a height of 48 and 109 m, were performed. The results include aspects such as walking speeds, physical exertion (oxygen consumption, heart rates and electromyography data), perceived exertion and behavioural changes, showing that physical work capacity affects walking speeds in case of long ascending evacuation and should be considered while using long ascending evacuation. Analysis of both walking and vertical speeds is recommended because it provides additional insights on the impact of stair configuration on vertical displacement and the importance of not using the same value for walking speed for different stairs because the design of the stairs has an impact. The novel datasets presented in this paper are deemed to provide useful information for fire safety engineers both for assisting fire safety design as well as the calibration of evacuation modelling tools.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Gao, Chuansi, et al.
(author)
-
Validation of standard ASTM F2732 and comparison with ISO 11079 with respect to comfort temperature ratings for cold protective clothing
- 2015
-
In: Applied Ergonomics. - : Elsevier BV. - 1872-9126 .- 0003-6870. ; 46:Online 17 July 2014, s. 44-53
-
Journal article (peer-reviewed)abstract
- American standard ASTM F2732 estimates the lowest environmental temperature for thermal comfort for cold weather protective clothing. International standard ISO 11079 serves the same purpose but expresses cold stress in terms of required clothing insulation for a given cold climate. The objective of this study was to validate and compare the temperature ratings using human subject tests at two levels of metabolic rates (2 and 4 MET corresponding to 116.4 and 232.8 W/m(2)). Nine young and healthy male subjects participated in the cold exposure at 3.4 and -30.6 °C. The results showed that both standards predict similar temperature ratings for an intrinsic clothing insulation of 1.89 clo and for 2 MET activity. The predicted temperature rating for 2 MET activity is consistent with test subjects' thermophysiological responses, perceived thermal sensation and thermal comfort. For 4 MET activity, however, the whole body responses were on the cold side, particularly the responses of the extremities. ASTM F2732 is also limited due to its omission and simplification of three climatic variables (air velocity, radiant temperature and relative humidity) and exposure time in the cold which are of practical importance.
|
|
| 9. |
- Gao, Chuansi, et al.
(author)
-
Whole body heat balance and local insulation required to prevent extremity cooling in extremely cold environments
- 2016
-
In: 6th International Conference on the Physiology and Pharmacology of Temperature Regulation. ; , s. 165-165
-
Conference paper (peer-reviewed)abstract
- IntroductionLocal cooling in winter conditions is a sensitive and early warning of whole body cooling. Previous studies showed that the equilibrium temperature for the 5th finger is strongly affected by both temperature and insulation. The international standard ISO 11079 is used to calculate clothing insulation required for the whole body based on heat balance equations. However, it does not provide possibility to determine required insulation for local protection. The European standard EN 511 has provided a simple example of the thermal insulation level required as a function of ambient air temperature at a wind speed below 0.5 m/s. The objective of this study was to investigate the relationship between glove insulation and finger temperature in an extremely cold condition.MethodsNine subjects participated in a climatic chamber (Ta -30.6 °C, Va 0.4 m/s). Hestra wind stopper fleece fabric gloves and thicker cross country ski mittens (727 g/m2) with micro fleece lining were used for four and five subjects, respectively. Cold protective clothing (Icl=1.89 clo, standard total insulation: 2.26 clo) was used for subjects walking at 232.8 W/m2 to provide whole body thermal comfort according to ASTM F2732. Results and conclusionsThe rectal temperature was relatively stable (37.4 - 37.7 °C) during walking (90 min). The mean little finger temperature reduced to 7.9 (SD 1.4) °C when wearing Hestra wind stopper fleece fabric gloves (0.95 clo), whereas the finger temperature reached 17.8 (1.2) °C when wearing thicker ski mittens (1.46 clo). The insulation of gloves is required to be approximately about the standard total insulation of the ensemble (2.26 clo) to maintain thermal equilibrium of the finger (33 °C). The relationship (Iglove = 0.0522 * Tfinger + 0.5347) between finger temperature (°C) and glove insulation (clo) is established to estimate glove insulation required in this extremely cold environment.
|
|
| 10. |
|
|
