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- Hargeby, Anders, et al.
(författare)
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Habitat-specific pigmentation in a freshwater isopod : Adaptive evolution over a small spatiotemporal scale
- 2004
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 58:1, s. 81-94
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Tidskriftsartikel (refereegranskat)abstract
- Pigmentation in the freshwater isopod Asellus aquaticus (Crustacea) differed between habitats in two Swedish lakes. In both lakes, isopods had lighter pigmentation in stands of submerged vegetation, consisting of stoneworts (Chara spp.), than in nearby stands of reed (Phragmites australis). Experimental crossings of light and dark isopods in a common environment showed that pigmentation had a genetic basis and that genetic variance was additive. Environmental effects of diet or chromatophore adjustment to the background had minor influence on pigmentation, as shown by laboratory rearing of isopods on stonewort or reed substrates, as well as analyses of stable isotope ratios for isopods collected in the field. In both study lakes, the average phenotype became lighter with time (across generations) in recently established stonewort stands. Taken together, these results indicate that altered phenotype pigmentation result from evolutionary responses to local differences in natural selection. Based on the assumption of two generations per year, the evolutionary rate of change in pigmentationwas 0.08 standard deviations per generation (haldanes) over 20 generations in one lake and 0.22 haldanes over two generations in the other lake. This genetic change occurred during an episode of population growth in a novel habitat, a situation known to promote adaptive evolution. In addition, stonewort stands constitute large and persistent patches, characteristics that tend to preserve local adaptations produced by natural selection. Results from studies on selective forces behind the adaptivedivergence suggest that selective predation from visually oriented predators is a possible selective agent. We found no indications of phenotype-specificmovements between habitats. Mating within stonewort stands was random with respect to pigmentation, but on a whole-lake scale it is likely that mating is assortative, as a result of local differences in phenotype distribution.
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| 2. |
- Ahnesjö, Jonas, 1969-, et al.
(författare)
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Benefits of outdoor exercise and recovery outdoors in elderly
- 2019
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Ingår i: HEPA Europe, Odense, Denmark, August 28-30, 2019. ; , s. 38-38
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Konferensbidrag (refereegranskat)abstract
- Purpose: The purpose of this study was to test the hypothesis that the ”outdoors” has an added health effect on top of that of physical activity. This hypothesis is based on the fairly extensive volume of evidens suggesting that the outdoor environment is beneficial for overall health. We, however, consider most previous studies insufficiently designed in order to draw causal relationship between spending time outdoors and examined health parameters. In this study we state that our experimental design allows us to do just that. Methods:In this randomized cross-over experimental design, 49 healthy subjects (+65 years, 27 female) performed a standardized submaximal bike ergometer test in three different environments (indoors, simulated outdoors and outdoors). The test consisted of 20 minutes cycling and subjects were instructed to stay between 11-13 at the Borg RPE scale (i.e. moderate intensity). Each test was followed by two hours of passive recovery. We measured power output, heart rate, lactate and counts of five fractions (lymphocytes, monocytes, neutrophiles, basophiles and eosinophiles) of white blood cells (leukocytes) in circulation. Results:Our results revealed that the outdoor treatment resulted in higher levels of lactate, higher heart rate and higher power output despite that there were no differences in Borg RPE-rating between the treatments. The white blood cell analysis showed an increase of circulating leukocytes in almost all fractions immediately post exercise in all treatments. Numbers decreased rapidly post exercise and the lymphocyte numbers stayed well under baseline for more than one hour during recovery. This is referred to as an “open window” where the immune function is temporarily suppressed and there is an elevated risk of infection of primarily URTI. Conclusions:Our results not only suggest that exercise is more efficient out of doors such that more exercise/effort is obtained but also that recovery outdoors may be a way to decrease the risk of infections due to exercise induced immune suppression. The risk of getting an infection is known to be generally lower out of doors. Taken together, our results support the notion that exercising and spending time outdoors indeed is beneficial for health in senior citizens.
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| 5. |
- Ahnesjö, Jonas, 1969-, et al.
(författare)
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Effects on white blood cells in senior citizens during post exercise recovery in three different environments (indoors, simulated outdoors and outdoors)
- 2016
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Konferensbidrag (refereegranskat)abstract
- IntroductionNatural environments are known to promote health and may also provide extraordinary conditions for post exercise recovery (Kuo 2015). In the project Health Effects of Recreation Outdoors (HERO) we explore the hypothesis that post exercise recovery in natural environments may be reflected in white blood cell counts (WBC). In our study 50 seniors (age >65 years) performed moderate physical activity (20 min) followed by passive recovery (2h) in three different environments (indoors, simulated outdoors and “true” outdoors).MethodThe experimental setup was a randomized cross-over design, thus all test persons did all treatments in a randomized order. We sampled white blood cells (WBC-diff), which were used to detect and quantify inflammatory response.ResultsOur early findings provide some support for the hypothesis that environment may impose differences in recovery effectiveness. White blood cell count (WBC-diff) appears to differ between the treatments and there is a significant interaction between sampling time and recovery environment in the monocytes, suggesting that the monocyte numbers differ, not only between sampling times but also between environments. In addition, WBC also show that some of the test persons develop leukocytosis during exercise and that white blood cell levels decrease rapidly immediately post exercise to levels significantly lower than base line values.DiscussionOur results suggest that moderate physical activity in senior citizens may result in acute leukocytosis (see e.g. Sand et. al. 2013) and that recovery effectiveness (e.g in monocyte response) may be dependent upon environmental factors. The clinical importance of our results are not fully understood but there has been suggested an “open window” immediately post exercise in which infection risk may be elevated (Pedersen & Toft 2000) and it is possible that recovery out of doors may reduce this risk.ReferencesSand, K., L, Flatebo, K., Andersen, M., B., Maghazachi, A., A. (2013) World J Exp Med 20; 3(1): 11-20Pedersen, B., K. & Toft, A., D. (2000) Br J Sports Med 34:246–251Kuo, M. (2015) Frontiers in Psychology 6:1-8
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| 6. |
- Ahnesjö, Jonas, 1969-, et al.
(författare)
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Organized recreational fishing in school, knowledge about nature and influence on outdoor recreation habits
- 2020
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Ingår i: Journal of Outdoor and Environmental Education. - : Springer. - 2206-3110 .- 2522-879X. ; 23:3, s. 261-273
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Tidskriftsartikel (refereegranskat)abstract
- In this study we have investigated the effectiveness of a one day school-basedintervention with recreational fishing (in Swedish called Klassdraget) in increasingenvironmental awareness, interest in nature and recreational fishing in pupils agedbetween 8 and 12. Our results suggest a weak positive association between exposure tonatural environments in a recreational fishing context and interest in nature andrecreational fishing. We found the intervention to have no effect on the frequency offishing, interest in fishing more, or number of visits in nature during spare time.Knowledge about nature and possibly also environmental awareness are positivelyaffected and these effects can be traced as long as three years after the intervention. Ourfindings also reveal a low correlation between frequency of nature visits and selfreportedinterest in nature. The observed effects of Klassdraget are small but appear tobe larger for girls, who are traditionally less interested in recreational fishing whencompared with boys.
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| 7. |
- Ahnesjö, Jonas, 1969-, et al.
(författare)
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Outdoor Exercise is More Efficient than Indoor Exercise in Senior Citizens. Physiological Evidence from the HERO Project
- 2018
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Konferensbidrag (refereegranskat)abstract
- INTRODUCTION: IntroductionPhysical exercise has been proven beneficial for health in all ages. In elderly, physical exercise, may contribute to prolonged life with maintained high quality and less costs associated with health care for society. In this study we explore if exercise out of doors may provide extra benefits as compared to exercise indoors and we measure power output, lactate levels and perceived effort in 49 senior citizens performing 20 minutes of moderate physical activity.METHODS:MethodThe HERO project is a randomized cross-over experiment with three different treatments . The study sample consisted of 49 healthy senior citizens. They performed 20 minutes moderate intensity physical activity on an ergometer bike in all three conditions. Before immediately after and at minutes 10, 20, 30, 60 and 120 we sampled blood lactate. Power output was computed at 7 occasions during the 20 minutes of cycling, as was the rating of perceived exertion . Data was analyzed using mixed linear models. RESULTS:ResultsOur findings show that there were no differences between the two indoor treatments in any of the measured variables. In the outdoor treatment, however, there were significant effects on blood lactate levels and power output but not in perceived exertion, suggesting that exercise out of doors makes the test person more efficient although the experience of effort stay unaffected.CONCLUSION:Discussion/conclusionsOur results support the notion that the outdoors may provide extraordinary conditions for exercise, not only because it appear to results in more exercise/effort, the outdoors is also an “arena” with high availability and most often totally for free. Previous results from the HERO project also suggests that white blood cell counts are affected by the outdoor treatment, something that may be related to the observed increased power output herein
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| 9. |
- Ahnesjö, Jonas, 1969-, et al.
(författare)
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Recreational fishing in an educational intervention context promotes awareness and knowledge about nature in schoolchildren
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Outdoor activities may be intuitively associated with interest for nature and environmental concern. However, most scientific studies suggest that no such correlation exists. In this quantitative study we have used a questionnaire and explored the hypothesis that a one day educational intervention may be a successful tool in increasing environmental awareness, interest for nature and interest for recreational fishing. We present evidence suggesting that educational interventions in which young people are exposed to natural environments in a recreational fishing context have positive effects on interest for nature and recreational fishing, knowledge about nature and environmental awareness. Our findings also reveal that frequency of nature visits does not correlate with self estimated interest for nature. We also show that the observed effects of the educational intervention “Klassdraget” appear to be larger for the girls which are, by tradition, less interested in recreational fishing as compared to boys.
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| 10. |
- Ahnesjö, Jonas, 1969-, et al.
(författare)
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The effect of exercising in different environments on heart rate and power output among older adults–a randomized crossover study
- 2022
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 17:11
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundA growing body of evidence suggests that exposure to nature is beneficial for human health. However, the observed health effect of nature may be mediated by physical activity and that humans are physically active at a higher intensity outdoors compared to when they are physical active indoors.ObjectiveThis study examines the variation of heart rate and power output for a fixed rating of perceived exertion in a group of healthy older adults in three different environments representing three levels of exposure to nature.MethodsTo this randomized, 3-by-3 crossover design study, healthy older adults (≥65 years) were recruited from local gyms. All participants participated in three experimental conditions; indoors, simulated outdoors and outdoor environments, in a randomized order. The participants exercised for 20 minutes at an intensity equivalent to a rating of 11–13 on the Borg scale for perceived exertion (RPE). Measurements of heart rate, power output (Watt) and ratings of perceived exertion were taken at minutes 1 to 6 and at minute 20. To examine the effect of the environment on heart rate and power, linear mixed models were used.ResultsIn all, 48 participants (56% females) were included in the analysis. No significant main effects on the outcomes were observed for power output (p = 0.073, η2 = 0.04) or heart rate (p = 0.067, η2 = 0.04)ConclusionNo significant effect on the outcomes was observed. However, borderline significant outcomes for power output or heart rate outdoors in nature, along with previous studies in the field, indicates that such an effect cannot be completely ruled out, but any effect is likely to be small. Future research examining health benefits of the independent exposure to nature are encouraged to adjust for the dose of physical activity.
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