You’d think as an Exercise Physiologist with 17 years experience I wouldn’t need a health coach. In fact I thought I had a pretty good handle on my health. As Max wrote about his experience in a previous blog, we’ve had the opportunity to use a Whoop band. So we thought we’d use the opportunity to learn more about our exercise, sleep and recovery. What I discovered both surprised and motivated me!
Apart from being a great accountability tool to help guide me on my sleep and exercise intensity, what I found most interesting was Whoop’s recovery metric. You see the Whoop band monitors both your heart rate and heart rate variability (HRV). It then gives you a score as to how well you’ve recovered.
HRV is a marker of “internal” stress
Now in a previous blog, not only did I describe what HRV is, but I also explained that it is a biomarker that responds to stress, inflammation and even food! You see, because HRV is a measure of the balance between our fight or flight response and our rest and digest response, anything that our body finds “stressful” or “inflammatory” has the potential to be picked up by a drop in your HRV.
What your body finds stressful is extremely individual. This depends on a multitude of factors including our genetics, immune function and the environment we live in. You see it can be almost impossible to work out, and I’ve spent many years exploring what works for me.
Using HRV as a marker, which is obviously only one of many potential health markers, can be a really useful way to work out what MY body finds stressful and impacts on my recovery.
So within a week with Whoop, I’ve already learnt (or reaffirmed) something about my diet that my body finds stressful.
So what did my 24/7 health coach reveal?
Here’s a screenshot of my recovery levels using the Whoop Dashboard. When your in the “green” zone you’re regarded as fully recovered, while the red zone indicates that you’ve got to tread carefully. This could be an indicator of training too hard, you’re recovering from an injury, or you might be coming down with sickness. For me it was none of these.
You see on the Saturday night I chose to have fried food and a couple of alcoholic drinks. Now I’ve had a few nights where I’ve had similar alcohol consumption and while it definitely affects my recovery it’s usually not enough to push me into the red zone.
So my thoughts are now directed toward the fried, fatty “pub meal” that I chose to eat that Saturday night. In particular how I felt that Saturday (and even Sunday) night! And as I explained in a previous blog, saturated and trans-fats are something has has been shown to affect your HRV.
What a good night’s sleep looks like for me
Just so you can see things a bit more visually I’ve included a graph or my heart rate on a “good” night, as well as my heart rate during the night after that meal.
Now my HRV on this “good” night was around 130, and thus far it is consistently between 100 and 140. This number varies with age, fitness and genetics so the score means very little. However it’s the change that matters.
So what did the bad night’s sleep look like?
On the bad night my HRV had dropped to 36, a very low score. You’ll see in the graph that my recovery score was only 13% as compared to 98% in the previous one.
What you’ll also notice between the two graphs is the difference in the heart rate overnight. You can see that it took most of the night for my heart rate to drop. My average resting HR is normally around 46, that night it was 63. This is 37% higher!
Now subjectively I woke up feeling bloated and very lethargic. This can happen from time to time and I often don’t think about it twice. But in my gut (pun intended), I’ve known that there are certain foods that don’t agree with me and I need to moderate.
Why Whoop is my 24/7 health coach
So now I’m extremely motivated as I now have a tool to help quantify my recovery. I can use this to work out my individual response to the multitude of factors that life throws at all of us! I’m seeing the Whoop band as my 24/7 health coach. Guiding me to make changes to my Food, Exercise, Sleep and Stress which at the end of the day will help make me fitter, healthier and improve my energy!
Click here for more information on our Whoop health coaching service.
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Now most of us know that our heart rate changes in times of stress. We feel it racing when there’s an impending deadline at work. It’s also well known that regular exercise lowers our resting heart and reduces our risk of many chronic diseases. But did you know that food can also affect heart rate?
Before I explain how food can impact on your heart rate, let me explain in a little more detail the way it does this.
Firstly, it’s important to know that a healthy heart rate does not beat regularly. For example if your resting heart rate is 60 beats per minute, we would not expect your heart to beat once every second. In fact, the variability in your heart rate has been shown to predict risk of premature death in people who have had a heart attack.
What is Heart Rate Variability?
Heart Rate Variability (HRV) is not new. In fact, we’ve been measuring (HRV) since the advent of the ECG in the 19th century. What we’ve learnt since then is that when a heart rate is more variable it tends to indicate better health.
Now HRV is a measure of the time difference between successive heart beats in what’s known as the RR interval (see figure below). You’ll notice that the two RR intervals in the figure below have a different RR interval, which is normal. If you have greater variability in the RR interval you are said to have a high HRV.
So while HRV is a measure of heart beats, the signal that creates the variability in the RR interval originates in your nervous system. Therefore our HRV is seen as a measure of the balance between two branches of our nervous system.
The parasympathetic branch controls things like digestion or your fingernails and hair growing. It is often thought of as the “rest and digest” system and it causes a decrease in heart rate.
The sympathetic branch controls our responses to things like stress and exercise. It is our “fight or flight” system and causes an increase in your heart rate.
When our nervous system is balanced it tends to send a lot of mixed messages. Tis result in lots of fluctuation and is highly responsive to change and we then see a high HRV. When one aspect of our nervous system takes over our HRV is less responsive and we get a low HRV.
If you’d like a more detailed explanation on heart rate variability, this article from Whoop makes it nice and clear.
What has HRV got to do with our health?
While HRV is seen as a measure of balance in our nervous system, because this system responds to exercise, psychological stress, inflammation and our underlying physiology it can be also seen as a marker of health.
In fact, changes in HRV correlates with CRP which is an inflammatory marker in your body. It has also been used to predict cardiovascular disease and diabetes (Young & Benton, 2018). Our HRV improves as we get fitter and healthier so it can be a really useful way to track our health.
How does food affect Heart Rate Variability?
You can see that HRV is more than a measure of stress and fitness level. But what we’re starting to learn is that your HRV will even respond to your diet. One well established link is that between our HRV and alcohol (Young & Benton, 2018). Both acute and chronic alcohol consumption causes a lower HRV.
Further to this, there is a growing pool of evidence to show that HRV responds to high blood sugar levels and it decreases as a response to saturated and trans-fats in our diet (Young & Benton, 2018). On the flip side a Mediterranean diet and omega-3 fat consumption tend to improve your HRV. Interestingly all of these food behaviours are all related to your long term health!
So those of you familiar with our FESS questionnaire (Food, Exercise, Stress, Sleep), will notice that changes in HRV respond to most of these behaviours in some way. Perhaps then using this measure could be another way to monitor our long term health?
This is something I’ve been exploring with myself using a “Whoop” band and I plan to share these personal insights in my next blog!
Click here for more information on our Whoop health coaching service.
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Many people don’t eat enough fruit and vegetables, and at a population level we seem to score under par. However, I’ve noticed an interesting seasonal trend with some of my clients over summer. One where if they tend to be prone to metabolic issues like weight gain and blood sugar control these tend to spike; and the common thread is fruit.
This got me to investigate, how much fruit should you eat? Is there such thing as consuming too much, and if so, what is it?
How much fruit according to the Australian Dietary Guidelines
Now back in the 2000s there was a relatively successful campaign called “Go for 2 and 5” which educated us on the Australian Dietary Guidelines. This tells us how much fruit and vegetable we should be consuming. The evidence seems to show that as a population we should be aiming for 2 serves of fruit and 5 serves of vegetables per day.
We know that it was a successful campaign, as over the campaign period the awareness of these ads went from 20% to 70% of survey respondents (Department of Health & Ageing, 2007). Interesting though, while 94% of respondents were able to correctively give the fruit consumption guidelines of 2 or more serves per day, only 32% correctly gave the correct response of 5 or more serves of vegetables.
This got me thinking. Do we have a confirmation bias when it comes to fruit and vegetable consumption? By this I mean that we tend to hear the message that we should be eating more of the lovely sweet stuff. But ignore the message regarding boring old vegetables.
Perhaps we thought the message was go for 5 and 2 rather than 2 and 5?
So does excessive fruit consumption matter to our health?
At least if we look at the report published on the success of the Go for 2 and 5 campaign we see that people were already consuming the guidelines of two serves of fruit per day on average. While the average serves of vegetables scraped in at just over half of the guideline at 2.6 serves. Interestingly, while we already succeeded as a nation at consuming 2 serves of fruit 43% indicated that they planned on increasing their fruit consumption. Only 28% planned on increasing their vegetables.
Certainly this appears as though the message of eating more fruit was much more palatable to survey respondents.
So it doesn’t surprise me then when I see a dramatic spike in how much fruit some of my clients eat over summer. This amount for some was up to 5-10 serves per day. Now clinically we saw increases in 1-2 kg of weight and spikes in blood sugar levels, even though these clients were doing what they thought was best for their health. They have listened to part of the message (the part which is most palatable for us sweet tooths!) and simply didn’t consider that you might be able to have too much fruit! West Cobb Dentistry experts recommend not to forget about the simple rules of proper dental care after meals.
In summer we tend to have an explosion of seasonal fruit to the market. Stone fruits, melons, and tropical fruits all tend to hit our grocery stores at a cheaper price. Interestingly, all of my clients who have drastically increased their consumption of fruits over summer had a stone fruit tree such as peaches and nectarines in their backyard.
So how much fruit should you eat per day?
Well that depends on what you may want to prevent health wise, but somewhere between 2-3 serves per day seems to be the “sweet spot”. If you want to know the science to this conclusion, and what fruits tend to work best for you, please read part two of this blog!
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So we established in Part 1 of this blog that the guidelines suggest that two or more serves is how much fruit we should consume. However, for some of us, it’s really easy to over consume. And this may well be having a negative impact on our health. Now I finished the previous blog with suggesting that somewhere between 2 to 3 serves is most ideal. But what if I have metabolic issues? Are there better and worse fruits to consume?
How much fruit should I consume to protect the heart?
Interestingly, many studies have looked into this question. However, they tend to combine fruit and vegetables together making it hard to conclude. One study by Lai et al (2015) looked into this and found that in a group of UK women the risk of death from a cardiovascular event decreased with more fruit even with over 4 serves per day. It’s would be easy from this to conclude that more is better right?
Another UK study looked at the risk of death from cardiovascular disease or cancer in both men and women (Oyebode et al 2013). What they found was that increased vegetable consumption was more protective than fruit. When they looked at just fruit intake the greatest benefit was at 3 serves per day. Depending on the model used, an increase in serves beyond this either had no further benefit or increased your risk.
How much fruit should I eat for metabolic health?
So we know that 3-4 serves of fruit is good for the heart. But what about people who are at risk of or want to prevent diabetes?
We have a good amount of evidence here that perhaps we shouldn’t be eating too much fruit. In fact a very large meta-analysis of 7 studies by Li et al (2015) concluded that those who had a fruit intake of around 200 grams per day (about 1.5 serves) were less at risk of developing diabetes. While it certainly is not good to have no fruit in a day, having 3-4 serves increased your risk comparatively. And from there, things tended to get worse with increased fruit consumption.
Furthermore, a study by Zhang & Jiang (2015) tended to corroborate this finding with two serves a day being the “sweet spot” for reducing the risk of developing diabetes in a study of over 200,000 individuals. And similar to the Li et al (2015) meta-analysis, they found a similar U shaped curve when consumption increased above 2 serves with 4 serves being as high a risk as having no fruit at all.
So there may be such thing as too much of a good thing. And like most things we need to consume fruit in moderation, especially if we’re at risk of diabetes and metabolic conditions.
But are some fruits better than others? Well the short answer to this question is “yes”
Fruits that when you consume more to have a health benefit
Interestingly, most studies will show that vegetables have a stronger association in reducing premature death than fruit (Oyebode et al 2013). However, some fruits, when you consume more tend to reduce your risk of either cardiovascular disease or diabetes.
Lai et al (2015) found that a greater intake of citrus was associated with a lower risk of fatal stroke in women. While grapes were seen to be more protective against a fatal cardiovascular event. When we look at the risk of diabetes, Alperet et al (2017) found that temperate fruit such as apples was associated with a loser risk of diabetes in women. Both citrus and grapes tended to lower the risk of diabetes for both men and women.
So it appears there are some common threads: citrus and grapes tend to reduce our risk. But what about fruits that perhaps aren’t so good for us to overconsume?
Fruits that may not be good for us when we over consume
Firstly, a common theme in most studies is that fruit juice is not fruit! Imamura et al (2015) found that while not quite as bad as soft drink (every serve a day increased your risk of diabetes by 18%), every serve of fruit juice increased your risk by 5%.
When it comes to increasing your risk of cardiovascular disease it seems that any canned fruit will do this (Oyebode et al, 2013). They found that every daily serve increased your risk by 17%.
Now there it appears that too much tropical fruits (bananas, mangoes, melons) will increase your risk of diabetes and these should be limited to less than one serve a day (Alperet et al 2017). Interesting Huang et al (2017) found that tropical fruit increased the risk of gestational diabetes.
Finally, Alperet et al (2017) also found that higher glycaemic index (GI) fruits had a greater risk than lower GI fruits. While these fruits tend to be more tropical in nature here’s a list of fruits with a GI greater than 50:
- Watermelon – 72
- Pineapple – 66
- Rock melon – 65
- Paw Paw – 60
- Canned Peaches – 58
- Banana – 56 (although increases with ripeness)
- Kiwi Fruit – 52
The take home message about how much fruit you should eat
- The amount of fruit you eat is important. 2-3 serves per day is probably best for your long term health but more than 4 may increase your your risk of metabolic conditions such as diabetes.
- Try and limit your consumption of high glycaemic fruits like tropical fruits and treat them as “treats”.
- Don’t count fruit juice as a fruit, if anything it should be treated more like soft drink
- Aim to get the bulk of your 2-3 serves of fruit a day from lower or moderate GI fruits. Fruits like grapes, apples and citrus all appear to reduce your risk of health conditions as you age.
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What do exercise and a diet high in fibre have in common? We’ve known for some time now that both of these are good for our gut health and decrease our risk of colon cancer. However, it seems as though there may something extra that fibre and exercise have in common, and it comes as a fatty acid called butyrate. This link between exercise, fibre and gut health will be explored, and you’ll see that the effects travel as far as the brain.
What actually is butyrate and what does it do?
Butyrate is a short chain fatty acid produced by our gut bacteria as they break down foods that are high in fibre. Resistant starches are a type of fibre, that are some of the best fuels for these butyrate producing bacteria (Bourassa 2016). These starches come in foods such as legumes, oats and starches that are cooked and cooled like potato and rice salads.
Now butyrate is an important fuel for the cells of our colon. In fact it supplies up to 70% of their energy (Bourassa 2016). Keeping your colon cells healthy is thought to be one of the reasons why higher butyrate levels decrease your risk of colon cancer by 50% (Matsumoto et al, 2008).
However, the benefits of butyrate go well beyond reducing our risk of colon cancer. This is because healthier gut membranes improve their integrity (how closely they bond together) allowing them to act as a better barrier, which has flow on effects to improving our immunity and reducing inflammation (Ji Wang et al, 2018).
What’s the evidence on exercise and gut health?
Most of the interest on the effect of exercise on butyrate levels started back in 2008. Matsumoto and colleagues showed that butyrate levels, and the bacteria that produce butyrate, were higher in rats that exercised versus a sedentary control.
In 2014 a group of Irish researchers found that professional rugby players had a greater diversity of gut microbiota than a group of sedentary controls (Clarke et al, 2014). However a signifiant limitation in this study was that professional athletes eat very differently than the general population. And these results could possibly be related to their diet and not their activity.
We had to wait until late last year when a group from the University of Illinois designed a study that looked at the impact of aerobic exercise on butyrate. Previously sedentary individuals were asked to exercise three times a week for a 6 week period (Allen et al 2017). What they found was that there is a link between butyrate, exercise, and gut health in humans.
Much like the rodent study back in 2008 they found that aerobic exercise increases the levels of butyrate along with the colonies of bacteria that produce butyrate. Interestingly this effect was most pronounced in lean subjects. The overweight group did still increase the colonies of the butyrate producing bacteria (not to the extent of the lean group) but they didn’t see an increase in butyrate levels in their stools.
Exercise and gut health can also improve your brain!
Now here is where it really gets interesting. The term “your gut is your second brain” has been well used over the last decade. This has been used to explain that the enteric nervous system of the gut is not only quite complex, but it also has the capacity to signal the brain via many neurotransmitters.
We know that butyrate can cross the blood brain barrier and it is well known to suppress HDAC (Histone deacetylase; Bourassa 2016). Now HDAC inhibitors will increase the expression of BDNF (Brain-derived neurotrophic factor) in the brain. This is important for memory and learning as BDNF is like fertiliser for the brain. It helps your brain cells grow in number and connections!
So where’s the research at?
An interesting experiment, albeit in mice, was published back in 2013 where mice were given an object recognition memory task that is usually not enough to form in either their short or long term memory (Intlekofer et al, 2013). They had a sedentary group and a group that was exercising 3 weeks before the task. They also had a sedentary and exercising group that was injected with butyrate.
The non-butyrate injected sedentary mice could not successfully remember the task 24 hours post initial exposure However, both the sedentary/butyrate injected group and the exercise group could. And when it came to remembering the task 7 days after the initial exposure, it was only the butyrate group that could.
It is important to know that the exercise group only did so for the 3 weeks leading up to the task, and not during the 7 days after the task. This highlights that to get the improved learning outcome, continual exercise exposure is needed.
This mechanism of increased BDNF release via butyrate is probably why we see that children who are fed a high fibre diet perform better in cognitive tasks than those on a low fibre diet (Bourassa 2016). And it could also be the reason why it shows promise in the treatment of neurodegenerative diseases (Bourassa 2016).
We also know that aerobic exercise has an effect on increasing BDNF levels, and this may be why individuals have a 20% improvement in learning tasks (Winter et al, 2007). So it makes sense to eat a high fibre diet and exercise at the same time right?
Take home points about exercise and gut health:
- It appears as though aerobic exercise continues to benefit our health in many different ways, and improving our gut health is another reason to be active. Aerobic exercise of around 30 to 60 minutes a few times a week can give you this benefit to your gut.
- Improve the diversity of your microbiota through eating foods that are high in butyrate producing fibre such as legumes, oats and potato salads.
- Combine this with regular exercise to improve the butyrate production of your gut as this have effects that travel to your brain.
- And while there is still much more research to be done, it seems to indicate that by doing this you are improving your capacity to learn and remember things, along with decreasing your risk of developing neurodegenerative conditions such as Alzheimer’s.
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