Effects of Solar Radiation on Human Function and Cognition

NCT04160741 | Completed

• 1 other identifier: 6. Solar radiation & Thermo
• Study Type: interventional
• Target: 7
• Locations: 1 country
• Sites: 1

Brief Summary

Solar radiation is a physical phenomenon which interacts with any human being throughout its life on earth. This interaction is associated with numerous physiological functions, as well as a broad spectrum of deleterious effects on human health and wellbeing. The aim of this study is to elucidate the effects of solar radiation on human function and cognition in environmental conditions characterized by the same thermal stress.

Conditions

Heat Stress; Heat Strain

Keywords

heat stress; heat strain; solar radiation; responses; cognition; thermal

Outcome Measures

Primary Outcomes (12)

• Heart rate

  Heart rate data were continuously monitored using a Polar Team system (Polar® Team 2, Polar Electro Oy, Kempele, Finland

  03 hours and 20 minutes

• Mean skin temperature

  Temperature at the skin surface area was continuously monitored using iButton sensors (type DS1921 H, Maxim/Dallas Semiconductor Corp., USA)

  03 hours and 20 minutes

• Core body temperature

  Core body temperature was assessed throughout the entire protocol using telemetric capsules (e-Celsius, BodyCap, Caen, France) that was given to the workers to ingest prior to their work shift

  03 hours and 20 minutes

• Skin blood flow

  Skin blood flow was measured throughout the entire protocol with a laser Doppler flowmeter (PeriFlux 4000, Perimed, Stockholm, Sweden) at right forearm (brachioradialis) and leg (gastrocnemius)

  03 hours and 20 minutes

• Sweat rate

  Sweat rate was measured throughout the entire protocol at three regions \[forehead, thigh (quadricep), and arm (bicep)\] using ventilated capsule method

  03 hours and 20 minutes

• Perceived exertion

  We used the Borg 20th Scale (6 = no exertion at all; 20 = maximal exertion)

  Participants were assessed at baseline and every half an hour up until the end of the protocol at "hour 3".

• Cognitive performance (Vigilance)

  Vigilance was assessed via vigilance test. In this task two squares arranged vertically. A pattern jumps from one square to the other. Sometimes the pattern remains in one square. In this case volunteers had to touch the screen of a tablet computer as fast as possible. The total duration for the current task was set to 6 minutes. This is a well-known vigilance test described in the Test for Attentional Performance and previously used in the literature.

  Participants were assessed at baseline, at 1 hour and 40 minutes, and at "hour 3".

• Thermal comfort

  Thermal comfort was assessed via the thermal comfort scale (1 = comfortable; 5 = extremely uncomfortable).

  Participants were assessed at baseline and every half an hour up until the end of the protocol at "hour 3".

• Thermal sensation

  Thermal sensation was assessed via the thermal sensation scale (-3 = cold; +3 = hot)

  Participants were assessed at baseline and every half an hour up until the end of the protocol at "hour 3".

• Cognitive performance (Divided Attention)

  Divided attention task incorporates both auditory and visual stimuli in parallel. During the test a number of visual stimuli (crosses) appear in a random configuration in a 4X4 matrix. At the same time volunteers hear high and low beeps in a random order. The task is to detect whether crosses form a square and at the same time two high or low beeps are emitted twice in a row. This is a well-known vigilance test described in the Test for Attentional Performance and previously used in the literature.

  Participants were assessed at baseline, at 1 hour and 40 minutes, and at "hour 3".

• Cognitive performance (Memory Test)

  This is a computerized version of Sternberg's memory task. In this task volunteers had to observe carefully a random sequence of one to six digits (0 to 9) painted in white and displayed for 1.2 seconds each. Thereafter, a two second delay was followed by a random test digit filled in yellow color. Participants had to response as fast as possible by pressing "yes" or "no" button to indicate where the yellow digit appeared in the previous sequence or not, respectively. In this test participants were tested in 24 trials.

  Participants were assessed at baseline, at 1 hour and 40 minutes, and at "hour 3".

• Cognitive performance (Reaction Time)

  In this task participants had to respond as quickly as possible, by untouching the screen, after receiving a visual or acoustic stimulus.

  Participants were assessed at baseline, at 1 hour and 40 minutes, and at "hour 3".

Study Arms (4)

Hot environment with radiation

EXPERIMENTAL

Exposure to hot environment (30°C WBGT) with radiation (800 W/m2) Exposure for 03:20:00: * rest (two hours) * work (cycling) at 100 W (one hour) * recovery (twenty minutes)

Other: Radiation and warm environment

Hot environment without radiation

EXPERIMENTAL

Exposure to hot environment (30°C WBGT) with radiation (0 W/m2) Exposure for 03:20:00: * rest (two hours) * work (cycling) at 100 W (one hour) * recovery (twenty minutes)

Other: Warm environment

Neutral environment with radiation

EXPERIMENTAL

Exposure to neutral environment (20°C WBGT) with radiation (800 W/m2) Exposure for 03:20:00: * rest (two hours) * work (cycling) at 100 W (one hour) * recovery (twenty minutes)

Radiation: Neutral environment with radiation

Neutral environment without radiation

ACTIVE COMPARATOR

Exposure to neutral environment (20°C WBGT) with radiation (0 W/m2) Exposure for 03:20:00: * rest (two hours) * work (cycling) at 100 W (one hour) * recovery (twenty minutes)

Other: Neutral environment without radiation

Interventions

Radiation and warm environment OTHER

Exposure to hot environment (30°C WBGT) with radiation (800 W/m2) Exposure for 03:20:00: * rest (two hours) * work (cycling) at 100 W (one hour) * recovery (twenty minutes)

Hot environment with radiation

Warm environment OTHER

Exposure to hot environment (30°C WBGT) with radiation (0 W/m2) Exposure for 03:20:00: * rest (two hours) * work (cycling) at 100 W (one hour) * recovery (twenty minutes)

Hot environment without radiation

Neutral environment with radiation RADIATION

Exposure to neutral environment (20°C WBGT) with radiation (800 W/m2) Exposure for 03:20:00: * rest (two hours) * work (cycling) at 100 W (one hour) * recovery (twenty minutes)

Neutral environment with radiation

Neutral environment without radiation OTHER

Exposure to neutral environment (20°C WBGT) with radiation (0 W/m2) Exposure for 03:20:00: * rest (two hours) * work (cycling) at 100 W (one hour) * recovery (twenty minutes)

Neutral environment without radiation

Eligibility Criteria

• Age: 18 Years - 75 Years
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Healthy non-smoker individuals who exercise at least three times per week

You may not qualify if:

• Non healthy individuals and smokers

Sponsors & Collaborators

• Petros Dinas: lead

Study Sites (1)

FAME Lab, Department of Exercise Science, University of Thessaly

Trikala, Thessaly, 42100, Greece

Location

MeSH Terms

Conditions

Heat Stress Disorders

Interventions

Radiation

Condition Hierarchy (Ancestors)

Wounds and Injuries

Intervention Hierarchy (Ancestors)

Physical Phenomena

Study Officials

• Andreas Flouris

  andreasflouris@gmail.com

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Senior Researcher in human physiology

Study Record Dates

• First Submitted: November 7, 2019
• First Posted: November 13, 2019
• Study Start: February 15, 2019
• Primary Completion: May 27, 2019
• Study Completion: May 27, 2019
• Last Updated: November 29, 2023

Record last verified: 2023-11

Data Sharing

• IPD Sharing: Will not share

Locations

GR (1)