Effect of Age and Coronary Artery Disease on Response to Snow Shoveling

Sheldahl, Lois M.; Wilke, Nancy A.; Dougherty, Sara M.; Levandoski, S C; Hoffman, Mariana; Tristani, Felix E.

doi:10.1097/00008483-199305000-00011

Cited by 7 publications

(11 citation statements)

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“…Men are potentially more likely than women to shovel, particularly after heavy snowfalls. Snow shovelling is a demanding cardiovascular exercise requiring more than 75% of the maximum heart rate, 12,14 particularly with heavy loads.…”

Section: Discussionmentioning

confidence: 99%

“…12,13 Intense arm effort, repetitive motion, static upright posture, peripheral vasoconstriction 14 and greater myocardial afterload all increase the risk of coronary plaque rupture and thrombus formation. 12,14 Risks may be exacerbated by exposure to cold temperatures, 13,14 which increases vasoconstriction and blood pressure, and consequently the preload, cardiac output and oxygen demand of the heart. 30 Sudden exposure to cold temperatures has been shown to lead to sympathovagal activation and arrhythmia, 31 and breathing cold air has been shown to reduce coronary blood flow.…”

Section: Discussionmentioning

confidence: 99%

“…[12][13][14] Snowfall is flagged as a possible MI risk factor in northern countries, 9,10,15,16 but evidence based on aggregate patient data is conflicting. 9,10,12,[15][16][17][18][19][20] Because the analysis of aggregate data can result in a loss of statistical power 21 and carries a risk of ecologic bias, 22 conclusive evidence of an association between snowfall and MI has yet to be established.…”

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Association between quantity and duration of snowfall and risk of myocardial infarction

Auger

Potter

Smargiassi

et al. 2017

CMAJ

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BACKGROUND: Although aggregate data suggest a link between snowfall and myocardial infarction (MI), individual risk has yet to be assessed. We evaluated the association between quantity and duration of snowfall and the risk of MI using nonaggregated administrative health data. METHODS:We used a case-crossover study design to investigate the association between snowfall and hospital admission or death due to MI in the province of Quebec, Canada, between November and April during 1981-2014. The main exposure measures were quantity (in centimetres) and duration (in hours) of snowfall by calendar day. We computed odds ratios (ORs) and 95% confidence intervals (CIs) for the association between daily snowfall and MI, adjusted for minimum daily temperatures. RESULTS:In all, 128 073 individual hospital admissions and 68 155 deaths due to MI were included in the analyses. The likelihood of MI was increased the day after a snowfall among men but not among women. Compared with 0 cm, 20 cm of snowfall was associated with an OR of 1.16 for hospital admission (95% CI 1.11-1.21) and 1.34 for death (95% CI 1.26-1.42) due to MI the following day among men. Corresponding ORs among women were 1.01 (95% CI 0.95-1.07) and 1.04 (95% CI 0.96-1.13). Similar but smaller associations were observed for snowfall duration (0 h v. 24 h) and MI. INTERPRETATION:Both the quantity and duration of snowfall were associated with subsequent risk of hospital admission or death due to MI, driven primarily by an effect in men. These data have implications for public health initiatives in regions with snowstorms.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Association between quantity and duration of snowfall and risk of myocardial infarction

Auger

Potter

Smargiassi

et al. 2017

CMAJ

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“…Shoveling snow includes both isometric and iso- tonic components and causes a rapid increase in heart rate, blood pressure, and O 2 consumption (14,19,52,53). Other cold weather activities, such as skiing and deer hunting, similarly increase myocardial O 2 demand (4,8,25).…”

Section: Discussionmentioning

confidence: 99%

Effect of cold air inhalation and isometric exercise on coronary blood flow and myocardial function in humans

Muller

Gao

Drew

et al. 2011

Journal of Applied Physiology

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Muller MD, Gao Z, Drew RC, Herr MD, Leuenberger UA, Sinoway LI. Effect of cold air inhalation and isometric exercise on coronary blood flow and myocardial function in humans. J Appl Physiol 111: 1694 -1702, 2011. First published September 22, 2011 doi:10.1152/japplphysiol.00909.2011.-The effects of cold air inhalation and isometric exercise on coronary blood flow are currently unknown, despite the fact that both cold air and acute exertion trigger angina in clinical populations. In this study, we used transthoracic Doppler echocardiography to measure coronary blood flow velocity (CBV; left anterior descending coronary artery) and myocardial function during cold air inhalation and handgrip exercise. Ten young healthy subjects underwent the following protocols: 5 min of inhaling cold air (cold air protocol), 5 min of inhaling thermoneutral air (sham protocol), 2 min of isometric handgrip at 30% of maximal voluntary contraction (grip protocol), and 5 min of isometric handgrip at 30% maximal voluntary contraction while breathing cold air (cold ϩ grip protocol). Heart rate, blood pressure, inspired air temperature, CBV, myocardial function (tissue Doppler imaging), O2 saturation, and pulmonary function were measured. The rate-pressure product (RPP) was used as an index of myocardial O2 demand, whereas CBV was used as an index of myocardial O2 supply. Compared with the sham protocol, the cold air protocol caused a significantly higher RPP, but there was a significant reduction in CBV. The cold ϩ grip protocol caused a significantly greater increase in RPP compared with the grip protocol (P ϭ 0.045), but the increase in CBV was significantly less (P ϭ 0.039). However, myocardial function was not impaired during the cold ϩ grip protocol relative to the grip protocol alone. Collectively, these data indicate that there is a supply-demand mismatch in the coronary vascular bed when cold ambient air is breathed during acute exertion but myocardial function is preserved, suggesting an adequate redistribution of blood flow. blood pressure; sympathetic nervous system; oxygen consumption; handgrip EXPOSURE TO COLD TEMPERATURES causes many physiological adjustments, most of which help prevent a fall in core body temperature. Specifically, peripheral vasoconstriction and shivering both raise blood pressure and effectively increase the work of the heart. These are known triggers of angina in clinical populations (33). Cardiac death is highest in the winter months, even in people who spend little time outdoors (45,54). While the effects of lowered skin temperature on cardiovascular function have been extensively studied (10,29,59,60), other mechanisms likely play a role in this process.Physical perturbation of the oropharynx and larynx elevates blood pressure in clinical settings (18,34), and laryngeal cold receptors have been identified in animals (38, 51). Previous studies (26,28,35,37) have shown that blood pressure, heart rate, and/or muscle sympathetic nerve activity are increased with cold air breathing in healthy humans. Acu...

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“…1 Such effects are exacerbated by the vasoconstricting and sympathovagal effects of cold-air inhalation, 2 which together may conspire to precipitate myocardial ischemia, plaque rupture, coronary artery thrombosis or arrhythmias. 3 Other patient factors such as underlying cardiopulmonary fitness, self-pacing, 4 circadian variation and the time of snow clearance, 5 and the use of automated or semi-automated snow removal devices, can further modify cardiovascular responsiveness. 1 In a linked research study, Auger and colleagues have used routinely collected data to determine an association between the quantity and duration of snowfall and the risks of acute myocardial infarction (MI) in Quebec, Canada, between 1981 and 2014.…”

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The eco–biological–behavioural perfect storm that follows heavy snowfall

Alter

2017

CMAJ

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Snow shovelling has long been known to be an activity that puts particular strain on the cardiovascular system. It incorporates repetitive dynamic aerobic and resistance activity, which induces a Valsalva manoeuvre and places disproportionate workloads on arm rather than leg muscles, resulting in raised heart rate, blood pressure and myocardial oxygen demand.1 Such effects are exacerbated by the vasoconstricting and sympathovagal effects of cold-air inhalation, 2 which together may conspire to precipitate myocardial ischemia, plaque rupture, coronary artery thrombosis or arrhythmias. 3 Other patient factors such as underlying cardiopulmonary fitness, self-pacing, 4 circadian variation and the time of snow clearance, 5 and the use of automated or semi-automated snow removal devices, can further modify cardiovascular responsiveness. 1In a linked research study, Auger and colleagues have used routinely collected data to determine an association between the quantity and duration of snowfall and the risks of acute myocardial infarction (MI) in Quebec, Canada, between 1981 and 2014. 6 Their findings add weight to our understanding that the act of snow shovelling in cold temperatures sets the stage for an eco-biological-behavioural "perfect storm," particularly among those physically deconditioned who have or who are at risk of heart disease. 3,7 Auger and colleagues' elegant study incorporates detailed region-specific weather conditions, including daily snowfall and temperature, with individual-level data on hospital admissions and vital statistics. The authors have determined that a heavy snowfall (20 cm v. 0 cm) is associated with a 16% relative increase in the odds of MI-related hospital admission and a 34% relative increase in the odds of death due to MI on the day after a snowfall among men. The adverse cardiovascular effects associated with snowfall were not apparent among women. This finding supports their a priori hypothesis that such sex-related differences were largely attributable to snow-shovelling activities, which would more likely be undertaken by men than by women. This is not the first study to have explored the effects of weather on cardiovascular events. A large body of evidence has established a higher incidence of MI during winter months than during the summer. 5,8 However, epidemiologic evidence associating snowfall and MI has been less consistent.9,10 Unlike most other epidemiologic studies, which incorporated aggregate ecologic data, Auger and colleagues used individual-level data and a time-stratified case-crossover study design, whereby each individual was used as his or her own control. Accordingly, weather conditions were the primary factor that differed between cases and controls. For the most part, the authors' use of the casecrossover design eliminates or substantially reduces the effects of confounders -traditional factors known to be associated with an increased risk of nonfatal and fatal MI, such as socioeconomic status, comorbidity and seasonality. Another strength of their study ...

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Effect of Age and Coronary Artery Disease on Response to Snow Shoveling

Cited by 7 publications

References 0 publications

Association between quantity and duration of snowfall and risk of myocardial infarction

Association between quantity and duration of snowfall and risk of myocardial infarction

Effect of cold air inhalation and isometric exercise on coronary blood flow and myocardial function in humans

The eco–biological–behavioural perfect storm that follows heavy snowfall

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