HUB3006F PRACTICALS
HEALTH PROFILE
Dietary intake assessment
Possible answers obtained for dietary intake
-
Quantity – what type of food, how frequently is it needed and how much
Quality – Adequacy: use DRIs, food groups, food, patterns
Patterns – When, where, how and why
The aims of using Dietary Intake Assessment
-
Screening for dietary intake problems
In-depth assessment of dietary intake
Dietary intake/pattern as the determinant of health outcomes
Monitoring of dietary intake as “treatment”/confounder in intervention studies
What?
-
Energy and nutrients (entire diets in detail/single nutrients?)
Other foods constituents (phytochemicals, food contaminants)
Specific foods (frequency and amount)
Food groups (frequency, number of portions)
Dietary patterns
Dietary diversity
Target group: specific characteristics which then lead to methodological implications
-
Infants and young children
Primary school children
Adolescents
Elderly
The illiterate
Other questions
The time frame of intake
-
Single day
Usual intake over the period, how long
Respondent burden
Accessibility respondent's costs/resources e.g time, staff, venue
Diet intake methods
a.
-
24-hour dietary recall
Food frequency questionnaire (ffq)
Estimated/weighed food record
24-hour recall
Recalls intakes
preceding portion sizes
Estimate portion sizes
Single 24-hour recall vs repeated 24 recalls
Strength
Large groups
No change in usual diet
Decrease respondent burden: they are
quick and relatively easy
Relies on short term memory
Electronic
Estimate group intake
Limitations
Depends on memory
Estimation of portion sizes to grams
Single recall doesn’t reflect the usual intake
Under/over reporting
Alcohol, bingeing, and obesity may lead to
underreporting
Omission/additions (phantom foods)
Experienced interviewer
b. Food Frequency Questionnaires
- List of food items
- Frequency of intake
- Quantified: includes estimation of portion sizes
- Non-quantified: only frequency of intake
- Semi-quantified (standard portion used for quantification)
Strength
Reduces respondent burden (selfadministered)
Machine-readable
Ranking of individuals
Diet can be linked to disease research
Looks at your usual intake
c.
-
Limitations
Food list isn’t always representative
Can be culturally insensitive
Grouping of foods e.g “yellow vegs”
oversimplifies dietary intakes
Memory (concept of frequency)
Estimation of portions to grams
Over/underestimation
Estimated/weighed food records
Food diary
Recording as you eat
Portions: either estimate (household measures/units to grams) or weighed (special
scales)
Number of days: 3 to 7 or even longer
Strength
Memory is not a factor
Detailed, accurate information
It tends to be a reflection of the usual
intake
Ranking of individual
electronic
Estimation of portion size
Limitation
Small samples of volunteers (weighed)
Alteration of the usual diet
Requires a literate respondent
Increased costs (scales)
More respondent burden (esp. weighed records)
More than 5 days may lead to respondent fatigue
“Coder fatigue”: analysing large amounts of data
from weighed food records can be labourintensive and time-consuming for researchers.
- Can use food models
- Other models like tennis balls, match box
- Household measures
- Line drawings
- Photographs
These portions would need to be converted to grams
Interpretation of dietary intake
Energy, macro and micronutrients
-
Dietary standards – DRIs
Dietary goals
Food/food group based
-
Food-based dietary guidelines
Variety
Foods/groups – reflect specific nutrients
Dietary patterns e.g. Mediterranean
SIGNS OF HYPERLIPIDEMIA
a. Arcus cornealus
Lipid deposits form a white circle around the iris
- Elderly people can develop this whiteness, but
not due to hyperlipidaemia but ageing.
b. Xanthelasma
Lipid deposits occurring around the eye
Foam cells histologically, a combination of
macrophages, lipids, and cholesterol deposits that
accumulate around the eyes.
c. Xanthoma
- Many different types
- Xanthomas can appear in different parts of the
body
- Eruptive Xanthoma – hypertriglyceridemia
- Lipid deposits in tendons e.g. Achilles tendon
xanthoma, joints
- Signs need to be confirmed with a biochemical
test
Total energy balance = energy intake – estimated energy requirement (EER)
-
A positive energy balance can result in weight gain and risk of obesity
Fat intake as % of total energy intake = [(intake of fat x 9 kCal)/(total energy intake)] x100
EXERCISE PHYSIOLOGY VO2 MAX
VO2 max is the maximal amount of oxygen used and transported during exercise. It is an
indicator of endurance fitness.
- Can be expressed in l/min and relative to body weight in ml/kg/min.
- Training improves VO2max
1.1 Calculate your partner’s estimated VO2 max value, providing all necessary calculations.
= 150m (number of laps) = 150 m (9) = 1350 m
1350 m/1000m = 1,35km
VO2max = (22.351 x 1,35km) – 11,288 = 18,89 ml/kg/min
1.2 Write your own Vo2max value, and compare this to your partners (2)
Partner VO2 max = 18.89 ml/kg/min
Mine = 42.35 ml/kg/min
I have a higher VO2 max.
1.3 By comparing your Vo2max value, which of you would you consider to have a higher
cardiovascular capacity? (1)
I have a higher VO2 max, thus I have a higher cardiovascular capacity.
1.4 List three factors influencing VO2max? (3)
Age, body size and sex.
1.5 At what time would you anticipate your partner achieving steady-state oxygen
consumption during the 12-minute run? (1)
About 3 minutes, this would be lower for elite athletes (1-2 minutes)
1.6 Pros and cons of 12-minute iron/copper run in estimating VO2max
Pros:
-
Doesn’t require specialised equipment or expertise to administer. Accessible to a
wider audience.
Cons:
-
Depends on running ability, this is a limitation for people with musculoskeletal
limitations. This compromises the accuracy of the results.
-
The results of the test may be influenced by factors such as motivation, and
environmental conditions. This introduces bias and affects the reliability of results.
SLEEP AND CIRCADIAN RHYTHM
Sleep assessment and monitoring.
a. Polysomnography (PSG)
- It’s the gold standard laboratory sleep measurement tool.
- It allows measurements for brain activity, heart activity, eye movement, muscle
activity, respiration and oxygen saturation.
Pros of PSG
-
Currently the gold standard method – for sleep staging
Diagnostic for some sleep disorders e.g. sleep apnoea, restless leg syndrome.
Cons of PSG
-
Inconvenient
Expensive
Requires specialised equipment and staff.
Doesn’t tell us about habitual sleep.
Not recommended for diagnosing CR-related sleep disorders or insomnia-type sleep
problems.
b. Wearable devices to measure sleep.
- They are available to the public.
- But they are not brilliant at measuring sleep ranges.
- They rely on multiple sensor inputs. This allows them to measure:
- Accelerometry, heart rate, body temp, blood [O2] and skin conductivity.
- The data collected is fed to an algorithm that estimates sleep-wake parameters, such
as total sleep time, and sleep efficiency.
c. Actigraphy – research-grade wearable
- It’s a type of an accelerometer
- It records activity (sleep and wakefulness) and light
Pros
-
Validated against PSG
Widely used by researchers
Provides information about sleep timing, duration, and fragmentation (important for
CR-related sleep disorders)
Cons
-
Expensive
Requires specialised software
Doesn’t tell us about sleep staging or any of the other sleep-related variables we
might be interested in
Total sleep time is the actual time sleep as estimated by Actiwatch based on movements.
Onset latency is the difference between “lights out” and the time at which the Actiwatch
estimates that you fall asleep.
Sleep efficiency is the total sleep time/time in bed i.e. the time you were asleep while in bed
trying to sleep.
No. of arousals is the number of times the Actiwatch estimates you wake up during the
night. Reflects how much your sleep is disturbed.
Arousal index is the average number of arousals you experience per hour of sleep.
Sleep patterns and timing
Sleep timing is the average bedtime, wake-up time and midpoints of sleep. They reflect
circadian regulation of sleep, societal restrictions and social adaptations.
Social jetlag is the difference between the midpoint of sleep on work and free days. The
greater the difference, the greater the lag (a form of circadian desynchronisation).
Regularity is good, it helps synchronise circadian rhythm…
Sleep regularity is based on the consistency of your bedtimes, wake-up times and sleep
duration. Within a 1.5h range variability is supported to be beneficial.
Catch-up sleep is the extension of sleep duration by more than 1.5h on the weekends (free
days), this signifies insufficient weekday sleep. This also creates metabolic disturbances.
Chronotype
-
Attribute reflecting morning or evening preference.
Measuring sleep quality
-
Uses Pittsburgh sleep quality index
Global PSQI score range: 0-21
Lower values = better quality
Good sleep quality: PSQI </= 5
Sub-scores: duration, disturbance, latency, overall quality, sleep efficiency
Measuring daytime sleepiness
-
Uses Epworth Sleepiness Scale (ESS)
ESS range: 0-24
The lower the value, the less daytime sleepiness you have.
Excessive daytime sleepiness: ESS score > 10
Insomnia Severity Index
ISI range: 0-28
The lower the value, the fewer insomnia symptoms you have.
ISI range
No insomnia
0-7
Sub-threshold
8-14
Moderate
15-21
Severe
>22
Obstructive sleep apnoea risk
S
T
O
P
B
A
N
G
Risk
Uses STOP-BANG questionnaire
Snoring
Tired
Observed
Pressure
Body mass index
Age
Neck circumference
Gender
Low
0-2
During daytime
Stop breathing during sleep
High blood pressure
Larger than 35kg/m2
Older than 50 years
Males: >/= 43cm. Female: >/= 41cm
Male
Intermediate
3-4
High
5-8
Healthy sleep
-
Restorative
No catch-up sleep on days off
No problem falling asleep at night
Sleep-wake patterns are aligned with the environment
Can sleep without sleep medication
One consolidated nocturnal sleep
Sleep sweet spot
-
Do you extend your sleep duration on weekends by >1.5 hours?
Do you take <5min to fall asleep at night?
Do you need to nap regularly?
Do you wake up unrefreshed?
Do you feel uncontrollably moody or struggle to control your emotions?
CVS RESPONSE TO EXERCISE, COFFEE, AND DIVING RESPONSE
-
P wave = atrial depolarisation
QRS = Ventricular depolarisation, masked atrial
repolarisation
T wave = ventricular repolarisation.
During exercise, the intervals decrease, and the
waves are much closer to each other.
Amplitude: is indicative of the blood pressure. Small
amplitude = low BP; large amplitude = high BP. During
exercise, the peripheral blood flow will produce small
peaks, whereas central blood flow produces higher
peaks.
Heart rate: the number of peaks/min
A. COFFEE EFFECTS
Over time,
-
The coffee increases heart rate
It decreases the peripheral blood pressure.
Increases central blood pressure.
It stimulates the sympathetic nervous system.
And results in a transient arrhythmia (irregular heart rhythm without a clearly
identifiable cause).
Measurement Resting
10-sec post 30-sec
60-sec
120-sec
exercise
postpostpost
exercise
exercise
exercise
Pulse
2.23
1.25
1.62
2.01
2.29
Amplitude
(mV)
Heart rate
85
123
115
101
88
(bpm)
The pulse amplitude represents the pulse's strength or intensity, indicating the volume of
blood being ejected from the heart per beat.
During exercise, blood is redirected from non-essential areas, such as peripheral vessels, to
the skeletal muscles to meet the elevated O2 demand. This decreases the pulse amplitude in
peripheral vessels. There is a transient decrease in the peripheral blood pressure. As the
body recovers, there is gradual vasodilation to the peripheral vessels.
B.
-
EXERCISE EFFECTS
During exercise, blood flow is directed to active skeletal muscles and vital organs.
After exercise, blood flow to the skin is increased.
After exercise, blood flow is directed to the skin and extremities to release body heat
generated by the muscles.
During exercise the R-R intervals decrease.
C. DIVING RESPONSE
Condition
Regular
breath hold
(BPM)
Regular breath Submerged
hold(pulse
breath hold
amplitude)
(BPM)
Resting
15 sec into
breath hold
30 sec into
breath hold
End of breathhold
Total time
breath hold
(sec)
72
69
0.65
0,61
71
65
Submerged
breath hold
(pulse
amplitude)
0.64
0.59
67
X
58
0.45
65
0.55
57
0.43
36
25
During breath-hold, both with diving and regular breath-hold, the body conserves
oxygen by reducing heart rate and redistributes blood to vital organs, such as the
brain and heart.
The heart rate when submerged declines at a faster rate than a normal breath hold.
This is because of the diving response that involves the body trying to conserve O2.
1. The parasympathetic nervous system is activated to decrease heart rate.
Bradycardia helps conserve oxygen by reducing the oxygen demand of the heart.
2. Peripheral vasoconstriction, blood is shunted to the brain and heart.
EXERCISE PERFORMANCE
At the beginning of exercise, there is a lag to the maximum oxygen used and transported
around the body. This lag is known as the O2 deficit.
-
O2 demand is immediate, the O2 supply occurs gradually.
During this period energy is supplied anaerobically. There is more reliance on the
phosphagen system and glycolysis. This lag is shorter in trained athletes relative to untrained
athletes. And steady state is reached earlier.
During steady state, energy is supplied by aerobic oxidation. After steady state/ end of
exercise, oxygen is still consumed. The O2 debt has 2 components: rapid component and
slow component. The rapid component represents the O2 consumed for the replenishment
of ATP store, O2 in tissues and phosphocreatine store. In the slow component, there’s the
oxidative conversion of lactate into glucose.
Sometimes EPOC is prolonged when:
-
Hot/humid conditions
Rapid increase in MR
Excessive depletion of ATP
Elevated blood lactate
Increased epinephrine levels.
EPOC is the excess oxygen consumed during recovery from exercise.
Effects of training
-
Recover sooner = smaller EPOC
Reach steady state sooner = smaller oxygen deficit
Indirect calorimetry
Energy expenditure can be estimated by measuring respiratory exchange. This is the volume
of carbon dioxide produced and oxygen consumed. RER/ RQ can be determined which gives
us an estimate of the relative fuel contribution by fats or carbohydrates.
RQ or RER = VCO2/VO2
Percentage error = ((Theoretical RQ – experimental RQ)/theoretical RQ) x 100
-
A small percentage error indicates that the experimental RQ closely matches the
theoretical, while a higher %error suggests a greater deviation between the 2 values.
Total Energy Expenditure (TEE) is divided into REE, PAEE, and TEF.
PAEE is the energy expended during physical activity. This can be measured using indirect
calorimetry. Accelerometers can monitor and record activity. They can detect multidimensional changes in direction (acceleration).
-
Fats would be burnt more at lower to moderate intensity
As well as during steady state, combinational training, prolonged exercise
Chester Step test
a) Estimated maximal HR = 220 – age
80% of maximal HR = (220 – age) x 0.8
Using the heart rate for each step, we can predict the maximal uptake of oxygen using the
age estimated maximal heart rate.
VO2max is influenced by sex, age and body size
-
This estimation does not take into consideration fitness level. Highly trained ind. May
have higher HRmax values than predicted by age alone, leading to overestimation of
VO2max.
-
May not apply to some individuals, it may not be appropriate for ind. With CVD
conditions.
Age-predicted formulas usually assume a linear decline. However, the relationship
may not be linear.
EXERCISE PRINCIPLE
TESTING BATTERY = a collection of tests designed to evaluate various aspects of an
individual’s fitness or performance.
Pros:
2 Analysing the results can provide insight on an athlete’s fitness
3 By using multiple tests, it provides detailed information relative to a single test.
Cons:
Confounder:
4 Participant characteristics such as age, sex, genetics and fitness level can influence the
test results.