The goal of this interventional study is to learn if exposure to coastal environments improves the physical and cognitive health of older adults over the age of 60. The main questions it aims to answer are: Does coastal exposure affect physical stress levels in older adults? Does coastal exposure affect self-reported stress levels in older adults? Does coastal exposure affect cognitive measures, such as sustained attention, in older adults? Does coastal exposure affect sleep quality in older adults? Is there a difference between the various components of coastal environments (e.g. dykes, dunes,...) in their effect on older adults' physical stress? This wil be a within-subject study, in which participants get exposed to both a coastal and an urban environment to compare their response to these environments. Participants will perform a coastal and urban walk on different days, equipped with wearable sensors (namely a wrist- and chestband) to measure various parameters such as heart rate and skin conductivity. Before, during and after the walk saliva samples will be collected for cortisol analysis. Before and after the walks they will also answer some questions (on e.g. overall demographics but also self-reported mental health) and perform cognitive tests (to study e.g. sustained attention).
Due to practical reasons regarding time, infrastructure and resources, the second phase with video exposure was cancelled.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
60
This is a "real-life" exposure to the coastal environment, in which participants walk to a bench, sit there for 15 minutes, followed by a walk of approximately 30 minutes. After the 15 minute sitting period, a saliva sample is collected. During the walk, participants are equipped with wearable sensors. The walking route is indicated on a map.
This is a "real-life" exposure to the urban environment, in which participants walk to a bench, sit there for 15 minutes, followed by a walk of approximately 30 minutes. After the 15 minute sitting period, a saliva sample is collected. During the walk, participants are equipped with wearable sensors. The walking route is indicated on a map.
Ghent University
Ghent, Belgium
Heart rate variability - Time-domain measures
During the entire protocol, both in the first and second phases of the study, interbeat intervals (IBIs) will be recorded using the Polar H10 chestband. From these IBIs, heart rate variability (HRV) measures will be calculated. Time-domain measures will be expressed in milliseconds (ms), including SDNN (Standard Deviation of NN intervals) and RMSSD (Root Mean Square of Successive Differences). These parameters provide insight into autonomic nervous system activity, particularly parasympathetic modulation.
Time frame: For a period of 2,5 to 3 hours
Heart rate variability - Frequency-domain measures
During the entire protocol, both in the first and second phases of the study, interbeat intervals (IBIs) will be recorded using the Polar H10 chestband. From these IBIs, heart rate variability (HRV) measures will be calculated. Frequency-domain measures, including low-frequency (LF) power, high-frequency (HF) power (expressed in milliseconds squared \[ms²\] or normalized units \[nu\]), and the LF/HF ratio (unitless), will be analyzed. These parameters provide insight into autonomic nervous system activity, with HF power primarily reflecting parasympathetic modulation and the LF/HF ratio indicating the balance between sympathetic and parasympathetic influences.
Time frame: For a period of 2,5 to 3 hours
Electrodermal activity
Electrodermal activity (EDA) of participants will be measured using the EmbracePlus wristband. EDA will be continuously recorded throughout the entire protocol, both during the first and second phases of the study. The primary EDA outcome measures include skin conductance level (SCL) and skin conductance responses (SCRs), both expressed in microsiemens (µS), These parameters provide insight into sympathetic nervous system activity and arousal dynamics.
Time frame: For a period of 2,5 to 3 hours
Salivary cortisol
Saliva samples will be collected in the first phase of the study, at 4 time points: before the exposure (baseline), after the seated exposure of 15 minutes, right after the walk, and 20 minutes after the walk. These saliva samples will be analysed for the presence of cortisol, which is expressed in nmol/L.
Time frame: At 4 time points: before the exposure (baseline), after the seated exposure of 15 minutes, right after the walk, and 20 minutes after the walk
Sustained attention - Total number of items processed
Sustained attention will be measured immediately before and after exposure to both environments, in both phases of the study. The validated d2 test of attention will be used for this. One outcome of this test is the total number of items processed (TN). This represents the total number of stimuli (letters) that a participant has scanned and attempted to process within the given time, with higher numbers indicating better sustained attention.
Time frame: Immediately before and immediately after the exposure to both environments (takes approximately 15 minutes)
Sustained attention - Performance
Sustained attention will be measured immediately before and after exposure to both environments, in both phases of the study. The validated d2 test of attention will be used for this. Another outcome of this test is the performance (P). This is calculated as the number of correctly marked target stimuli minus the number of errors (including both commission and omission errors). The higher this performance score, the better the participants' sustained attention.
Time frame: Immediately before and immediately after the exposure to both environments (takes approximately 15 minutes)
Sustained attention - Error percentage
Sustained attention will be measured immediately before and after exposure to both environments, in both phases of the study. The validated d2 test of attention will be used for this. Another outcome of this test is error percentage. This indicates the percentage of errors relative to the total number of marked items. Errors can be divided into: 1) commission errors (false positives) and 2) ommission errors (false negatives). Commision errors represent the incorrectly marked symbols that are not target stimuli. The ommission errors are the target stimuli that weren't marked. The lower the error percentage, the better participants' sustained attention.
Time frame: Immediately before and immediately after the exposure to both environments (takes approximately 15 minutes)
Processing speed - Total correct responses
Processing speed will be measured immediately before and after exposure to both environments, in both phases of the study. The validated Symbol Digit Modalities Test will be used for this. One outcome measure is the number of total correct responses. This is the number of correct symbol-digit pairings made within the given time limit. The higher this number, the better participants' processing speed.
Time frame: Immediately before and immediately after the exposure to both environments (takes approximately 15 minutes)
Processing speed - Error rate
Processing speed will be measured immediately before and after exposure to both environments, in both phases of the study. The validated Symbol Digit Modalities Test will be used for this. Another outcome measure of this test is the error rate, which is the number of incorrect responses. The lower the error rate, the better for participants' processing speed.
Time frame: Before and after the exposure to both environments (takes approximately 15 minutes)
Perceived stress
Perceived stress will be evaluated immediately before and after exposure to both environments. This will be measured using one question asking the participant "How stressed are you now?", which has to be scored on a ten-point Likert scale ranging from 1 (labelled "Not at all stressed") to 10 (labelled "Totally stressed").
Time frame: Immediately before and after exposure to both environments
Perceived mental exhaustion
Perceived mental exhaustion will be evaluated immediately before and after exposure to both environments. This will be measured using one question asking the participant "How mentally exhausted are you now?", which has to be scored on a ten-point Likert scale ranging from 1 (labelled "Not mentally exhausted at all") to 10 (labelled "Totally mentally exhausted").
Time frame: Immediately before and after exposure to both environments
Positive mood and negative mood
Positive mood will be evaluated immediately before and after exposure to both environments. This will be measured using the "Positive and Negative Affect Schedule". Participants will have to indicate to what extent they experience each of the emotions or feelings listed on a scale ranging from 1 (labelled "Very slightly or not at all") to 5 (labelled "Extremely").
Time frame: Immediately before and after exposure to both environments
Sleep quality
In the first phase of the study, participants will keep a sleeping diary for 14 days, to see whether the exposures to the different environments have an effect on their sleep quality.
Time frame: 14 days
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