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- Alametsä, Jarmo, et al.
(författare)
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Age-related circulatory responses to whole body cooling: observations by ballistocardiographic EMFi sensors
- 2014
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Ingår i: 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
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Konferensbidrag (refereegranskat)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.
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| 2. |
- Alametsä, Jarmo, et al.
(författare)
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Age‐related circulatory responses to whole body cooling: observations by heart rate variability
- 2015
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Ingår i: Finnish Journal of eHealth and eWelfare. - 1798-0798. ; 7:2-3, s. 57-64
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Tidskriftsartikel (refereegranskat)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.
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| 3. |
- Kuklane, Kalev, et al.
(författare)
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Does reduced heat production during mild whole body cooling override increased heat generation by pre-shivering muscle tension?
- 2011
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Ingår i: Environmental Ergonomics. ; XIV, s. 112-115
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Konferensbidrag (refereegranskat)abstract
- INTRODUCTION Preshivering thermogenesis (developing muscle tension) may not be noticed in static situations due to reduced metabolism under mild body cooling. This paper describes the observations of metabolic and heart rate changes under mild body cooling. METHODS Eight men participated in the study. The subjects were dressed in shorts, socks and shoes, and were seated. The air temperature (32 °C) was after 25 minutes gradually reduced to 13°C (0.2 °C/min). Rectal, finger, central skin and air temperatures were recorded. Heart rate was measured continuously. Oxygen consumption was analysed under 5 minutes at 30th and 90th minutes. RESULTS AND DISCUSSION Metabolic rates were commonly decreasing (57((+/-)8 at 30th and 55(+/-)11 W/m2 at 90th minute) during cooling. In one subject (quickest finger cooling and increased final core temperature) the metabolic rate did not reduce. His momentary AVAs reaction indicates a more complex neural input than core cooling. In one subject onset of strong shivering raised metabolism considerably. The mean heart rate of all subjects followed the major trend in metabolic rate (80(+/-)12 at 30th and 72(+/-)12 beats/min at 90th minute). CONCLUSION Increased metabolic rate under mild cooling was not observed, eventually due to the absence of strong enough thermo regulatory responses such as increased muscle tension and superficial shivering. There is a need to repeat the study involving EMG in order to separate thermoregulatory effects from postural effects.
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| 5. |
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| 6. |
- Luomala, Matti J., et al.
(författare)
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Adding a cooling vest during cycling improves performance in warm and humid conditions
- 2012
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Ingår i: Journal of Thermal Biology. - : Elsevier BV. - 0306-4565. ; 37:1, s. 47-55
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Tidskriftsartikel (refereegranskat)abstract
- It is known that warm and humid environment reduces human physical performance. The present study examined whether the use of an ice-vest in such conditions can improve cycling performance. Seven participants cycled with consecutive, non-stop, 10-minute cycles of nine minutes at 60% of their (V) over dot O-2 max punctuated by a one-minute sprint at 80% (V) over dot O-2 max. The cycling protocol was continuously repeated until exhaustion. The protocol was performed with the ice-vest (ICE), worn after 30 min of cycling, and without the ice-vest throughout the protocol (CON). Ventilatory and thermal responses were continuously recorded. Electromyographic (EMG) signals from four muscles of the dominant leg were recorded over one minute, and subjective sensations were evaluated at 10-minute intervals. At exhaustion, the exercise time was recorded. Exercise time improved significantly while wearing the ice-vest from 61 min and 29 s to 74 min and 14 s (+21.5% +/- 7.6: p <0.05). Mean power frequency and amplitude of the EMG revealed decreased neuromuscular fatigue during ICE compared to CON. Ventilatory responses indicated a tendency towards lower ventilation, respiratory quotient was significantly lower and both thermal parameters and subjective sensations indicated lower thermal strain during ICE in comparison to CON. These results suggest that wearing an ice-vest during cycling in warm and humid conditions decreases thermal and physical strain, thereby improving cycling performance. (C) 2011 Elsevier Ltd. All rights reserved.
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| 7. |
- Potapov, Ilya, et al.
(författare)
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Nonlinear effects of winter swimming and sauna recreational activities on the heart rate variability
- 2017
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Ingår i: Computing in Cardiology. - 2325-8861. ; 44, s. 1-4
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Tidskriftsartikel (refereegranskat)abstract
- Sauna sessions and winter swimming are traditional and popular recreational activities in certain countries. Their positive effects on health and relaxation, both as separate and combined activities, are commonly reported. However, systematic studies of these effects are relatively scarce, especially regarding the nonlinear analysis of the physiological measurements of the heart activity. We performed Multi-Scale Entropy (MSE) and Detrended Fluctuation (DFA) analyses on the inter-beat time series (about 72 h long) of 21 healthy volunteers studied in three distinct contexts: winter swimming combined with sauna bathing (W), sauna bathing alone (S), and control (C) with no related activities. We confirmed that the scaling exponents (DFA) and complexity indices (determined from MSE) stay within the variation observed for healthy individuals as compared to public data sets. Next, we showed that S and W interventions have uncorrelated effects on the whole time series complexity in each individual. Additionally, the long-range scaling properties of S and W groups are not correlated as determined by DFA. Thus, we speculate that winter swimming combined with sauna bathing and sauna bathing alone might have different physiological responses.
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| 8. |
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| 9. |
- Smolander, Juhani, et al.
(författare)
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Effectiveness of a light-weight ice-vest for body cooling while wearing fire fighter’s protective clothing in the heat
- 2004
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Ingår i: International Journal of Occupational Safety and Ergonomics. - 2376-9130. ; 10:2, s. 111-117
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to examine the effects of wearing an ice-vest (ca 1 kg) on physiological and subjective responses in fire fighters. The experiments were carried out on a treadmill in a hot-dry environment. The physical cooling effect of the ice-vest was measured with a thermal manikin. The ice-vest effectively reduced skin temperatures under the vest. On average, heart rate was 10 beats min-1 lower, amount of sweating was reduced by 13%, and subjective sensation of effort and warmth were lower during work with the ice-vest compared to work without it. Thermal manikin tests indicated, that the useful energy available from the vest for body cooling was rather high (58%). In conclusion, the ice-vest reduces physiological and subjective strain responses during heavy work in the heat, and may promote efficient work time by 10%.
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