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Cardiovascular Responses to Cold in Hypertension (ColdHTN)

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ClinicalTrials.gov Identifier: NCT02007031
Recruitment Status : Completed
First Posted : December 10, 2013
Last Update Posted : December 11, 2013
Information provided by (Responsible Party):

Study Description
Brief Summary:

Wintertime is associated with increased morbidity and mortality and a majority is related to cardiovascular causes, such as myocardial infarctions, heart failures, and strokes. It is also known, that both acute and long-term cold exposure increase blood pressure and cardiac workload, and this may contribute to the observed excess morbidity and mortality during the cold season.

Although the effects of cold on blood pressure are known among healthy people, these responses among risk groups, such as hypertensive people, are not established. In addition, changes in cardiac electrical activity or autonomic regulation are largely unknown. The cardiovascular responses in the cold could be different among hypertensive people because of disturbances in the circulatory regulation or function, such as aortic stiffening and increased vasomotor tone of peripheral arteries due to endothelial dysfunction associated with the disease. To assess this, a controlled experiment employing a cold exposure similar to everyday winter circumstances in a subarctic climate was performed.

Condition or disease

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Study Design

Study Type : Observational
Actual Enrollment : 91 participants
Time Perspective: Cross-Sectional
Official Title: Cardiovascular Responses to Cold Exposure in Hypertension
Study Start Date : January 2010
Primary Completion Date : November 2011
Study Completion Date : November 2011
Groups and Cohorts

Hypertensive subjects
Hypertensive subjects are exposed to brief cold exposure (-15 C for 15 min) mainly subjected to their facial region during which their cardiovascular responses are registered.
Normotensive subjects
Normotensive subjects are exposed to brief cold exposure (-15 C for 15 min) mainly subjected to their facial region during which their cardiovascular responses are registered.

Outcome Measures

Primary Outcome Measures :
  1. Blood pressure response of hypertensive and normotensive subjects to cold exposure [ Time Frame: 2 hours (measured within the controlled experiment) ]
    The study assesses the blood pressure response of hypertensive and normotensive subjects to facial cooling. Blood pressure is measured before (warm, +18°C), during (cold, 15°C) and after (warm, +18°C) the employed cold exposure. The duration of each of these exposures are 30, 15 and 30 min.

Secondary Outcome Measures :
  1. Cardiac autonomic regulation [ Time Frame: 2 hours (measured within each controlled experiment), ECG recorded continuously ]
    ECG is recorded continuously during the controlled experiment (15 min warm 18 C, 15 min cold exposure -15 C and 20 min 18 C) from where cardiac electrical function, as well as autonomic nervous system regulation is assessed.

Eligibility Criteria

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Ages Eligible for Study:   55 Years to 65 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
The study participants were included according to a population based recruitment where a random sample of 1000 men (55-65 years old) living in Oulu, Finland was drawn from the Finnish Population Register. They were screened by telephone interviews for eligibility for the study. Eligible attendees measured their blood pressure home for a week according to the recommendations of the European Society of Hypertension and were classified either to hypertensive (systolic blood pressure ≥135 and/or diastolic blood pressure ≥85 mmHg) or normotensive (blood pressure <135/85mmHg). For the study we aimed at a 2:1 ratio of hypertensive and normotensive. The final study group consisted of 56 hypertensive and 35 normotensive middle-aged men.

Inclusion Criteria:

  • Measured BP (home measurements of one week) above 135/85 mmHg were selected to the group of hypertensive subjects.
  • Those with BP below 135/85 mmHg were selected as controls.

Exclusion Criteria:

  • Presence of coronary heart disease, respiratory diseases, and the use of antihypertensive drug treatment.
  • an average home BP ≥175/105 mmHg, initiating antihypertensive drug treatment, failed home BP measurements, and having a respiratory infection within a week prior to the controlled measurements
Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02007031

University of Oulu
Oulu, Finland, FI90014
Finnish Institute of Occupational Health
Oulu, Finland, FI90220
Sponsors and Collaborators
University of Oulu
National Institute for Health and Welfare, Finland
Finnish Institute of Occupational Health
Verve Research, Oulu, Finland
Principal Investigator: Tiina M Ikäheimo, Ph.D. University of Oulu
Principal Investigator: Jouni JK Jaakkola, MD, Ph.D. University of Oulu
More Information

Additional Information:

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Tiina Ikäheimo, Postdoctoral researcher, University of Oulu
ClinicalTrials.gov Identifier: NCT02007031     History of Changes
Other Study ID Numbers: 24300771KYTEM
First Posted: December 10, 2013    Key Record Dates
Last Update Posted: December 11, 2013
Last Verified: December 2013

Keywords provided by Tiina Ikäheimo, University of Oulu:
Cold temperature
Blood pressure

Additional relevant MeSH terms:
Vascular Diseases
Cardiovascular Diseases