Martin H. Sellens

The mental and physical health outcomes of green exercise

Abstract Both physical activity and exposure to nature are known separately to have positive effects on physical and mental health. We have investigated whether there is a synergistic benefit in adopting physical activities whilst being directly exposed to nature (‘green exercise’). Five groups of 20 subjects were exposed to a sequence of 30 scenes projected on a wall whilst exercising on a treadmill. Four categories of scenes were tested: rural pleasant, rural unpleasant, urban pleasant and urban unpleasant. The control was running without exposure to images. Blood pressure and two psychological measures (self-esteem and mood) were measured before and after the intervention. There was a clear effect of both exercise and different scenes on blood pressure, self-esteem and mood. Exercise alone significantly reduced blood pressure, increased self-esteem, and had a positive significant effect on 4 of 6 mood measures. Both rural and urban pleasant scenes produced a significantly greater positive effect on self-esteem than the exercise-only control. This shows the synergistic effect of green exercise in both rural and urban environments. By contrast, both rural and urban unpleasant scenes reduced the positive effects of exercise on self-esteem. The rural unpleasant scenes had the most dramatic effect, depressing the beneficial effects of exercise on three different measures of mood. It appears that threats to the countryside depicted in rural unpleasant scenes have a greater negative effect on mood than already urban unpleasant scenes. We conclude that green exercise has important public and environmental health consequences.

Green exercise in the UK countryside: effects on health and psychological well-being, and implications for policy and planning.

Abstract There is evidence that contact with the natural environment and green space promotes good health. It is also well known that participation in regular physical activity generates physical and psychological health benefits. The authors have hypothesised that ‘green exercise’ will improve health and psychological well-being, yet few studies have quantified these effects. This study measured the effects of 10 green exercise case studies (including walking, cycling, horse-riding, fishing, canal-boating and conservation activities) in four regions of the UK on 263 participants. Even though these participants were generally an active and healthy group, it was found that green exercise led to a significant improvement in self-esteem and total mood disturbance (with anger-hostility, confusion-bewilderment, depression-dejection and tension-anxiety all improving post-activity). Self-esteem and mood were found not to be affected by the type, intensity or duration of the green exercise, as the results were similar for all 10 case studies. Thus all these activities generated mental health benefits, indicating the potential for a wider health and well-being dividend from green exercise. Green exercise thus has important implications for public and environmental health, and for a wide range of policy sectors.

Preimplantation mouse embryos express Mhc class I genes before the first cleavage division

We have used oligonucleotide primers complementary for polymorphic regions of the mouse H-2D gene in a highly sensitive polymerase chain reaction (PCR) assay to detect the transcription of maternal and paternal class I mRNAs in gametes and preimplantation embryos. Using congenic strains of mice differencing only at the major histocompatibility loci, class I (H-2D) mRNA of both the maternal and paternal haplotypes was demonstrated in embryos from the one-cell zygote to the late blastocyst stage of development but could not be detected in vas deferens or in vitro capacitated sperm or in ovulated secondary oocytes. These data clearly show that both paternally and maternally inherited Major histocompatibility complex (Mhc) class I genes are transcribed from the earliest stages of embryonic development, and suggest that developmental regulation of expression of their protein products is principally at the post-transcriptional level.

Lectin receptors on the peri- and early post-implantation mouse embryo

SummaryMouse embryos at the blastocyst, blastocyst outgrowth, and primitive streak (day 7.5) stages of development were analysed for expression of lectin receptors using a panel of six FITC-conjugated lectins with affinities for five distinct saccharides (BSL, ConA, DBA, LTL, UEA and WGA). Blastocyst trophoblast expressed receptors for all the lectins but later tissues of the trophectoderm lineage lost receptors for distinct but overlapping subsets of the lectin panel. The inner cell mass (ICM) of the early blastocyst lacked receptors only for UEA. Differentiation of primary endoderm was accompanied by the aquisition of UEA receptors but subsequent differentiation into visceral and parietal endoderm involved the loss of receptors for both fucose binding lectins (UEA and LTL). Embryonic ectoderm in the day 7.5 egg cylinder retained receptors only for ConA and WGA. Thus, in general, differentiation during the peri- and early post-implantation period was associated with a differential loss of lectin receptors in all cell lineages of the mouse conceptus.

Estimation of Lactate Threshold by Near Infrared Spectroscopy

The anaerobic or lactate threshold (LT) is defined as the point at which blood lactate levels rise significantly above basal levels and correlates with athletic performance in endurance events (Weltman, 1995). Currently gas exchange measurements of whole body VO2 and VCO2 are the best non-invasive techniques of measuring the LT (Beaver et al., 1986). Near-infrared spectroscopy (NIRS) data has shown a correlation between muscle deoxygenation and blood lactate concentration (Rundell et al., 1997) and it has recently been suggested that NIRS can be used to determine the LT (Belardinelli et al., 1995; Bhambhani et al., 1997). NIRS provides a non-invasive method for the continuous measurement of changes in muscle haemo(myo)globin oxygenation and blood volume (Chance et al, 1992; Ferrari et al., 1997; Wilson et al., 1989). By identifying particular trends in the rate and extent of muscle deoxygenation these authors have shown correlations with gas exchange methods of measuring the LT.