Lesson video

Hi, everybody.

I'm Mrs. Brookes, and today I'm going to be talking to you about hydration.

You've been learning lots around diet and a balanced diet and those key nutrients within your diet.

But today's lesson we're gonna hone in specifically onto that water aspect and looking at hydration.

It might be a good opportunity for you to reflect on your own hydration in terms of how much you do drink on a daily basis.

But we're gonna go a little bit further than that and look specifically at that importance of hydration, particularly when you are playing or involved in sport and physical activity.

So our outcome of today's lesson is exactly that.

We are gonna look more at those effects of dehydration, so when you've not had enough water, and how that then can really have consequences on you being able to play sport effectively.

Our keywords are all very much linked to this concept of hydration.

So as I just shared with you there, that's having enough water to make sure that our body functions and functions well.

If we're in a state of dehydration, that means when we are gonna have lost some of that water, and therefore that function isn't gonna work as well.

You can see that word excessive.

So when we're in that dehydrated state, there's been that real severe loss of water or not sufficient amount of water.

Therefore, the function of the body can change.

We can see reaction time there is a keyword.

You'll be familiar with that from Paper 1, knowing that that's very much the time taken to initiate a response to a stimulus.

That is something that, because of this change in functioning, can be impaired as a result of that dehydrated state.

Rehydration is exactly kind of how it says it or how it feels.

That's when you're then gonna take on enough fluids, specifically water, to get yourself in that hydrated state.

We've also got this keyword here of viscosity.

We're gonna talk about that as we move through the lesson, but when you see it, just a reminder that that's talking about the blood becoming thicker.

And as a result of that, well, there are a few consequences as a result of that, many of which we're about to explore.

So our lesson is divided into two parts.

The first part is where we'll look at those effects of dehydration.

And when we feel confident with that, we'll move on to that second part and develop our skill of evaluation and how those consequences can have real impact on sport and physical activity.

So let's get started.

We're gonna start with Jacob, and he's sharing with us here that he plays squash, and he's always reminded by his coach to make sure that, when they come to training, they bring at least two litres of water.

So we can see there that the coach is obviously quite familiar with hydration and is reminding the athletes that, one, they need to bring that water, but, two, almost giving them like a recommended daily amount of what they need to bring.

And I suspect what the coach is doing there is really making sure that those athletes, including Jacob, are not going to experience that dehydration.

Remember, we said that's when the body loses an excessive amount of water and the function of the body is interrupted.

So Jacob's coach there knows that they can't really risk that interruption of functioning 'cause that's gonna impair their performance.

So Jacob at this point is kind of asking the question, "Well, how do we lose the water?" That's a good question and a good starting point because that does provide context in terms of why we need to hydrate and why it's important to restore that loss of water.

Sam answers this really well.

Sam says that at training there's that real feeling of being warm and aware of that sweat that's happening, both of which are to try and regulate the body's core temperature and allow the body to cool down.

And the coach will know that.

The coach, like Sam, will know that there's that sweat that is happening as well as that opportunity to try and make sure that the body isn't overheating.

And a lot of that water is lost through that sweating process.

So as a result, that water, that intake needs to make sure that it is at a point where you are making sure that you've got that correct functioning and you are in that hydrated state.

And what we're trying to offset is those feelings of dehydration that can come as a result of that sweating and that loss of water.

Which leads us on to talk about what those consequences are.

And there's a keyword there, impair, and there's lots of research around that, if you are in that dehydrated state, then the performance will be hindered or impaired in some way.

So that means that it will get worse or it won't be as good as it normally is.

So before we start looking at those consequences, let's do one of our first checkpoints.

And we've got a question here, a true/false question, asking if dehydration is a direct result of not drinking enough fluids before sport.

Tricky question, this.

Do we think that's true or false? Well done if you actually went with false.

And if you did, maybe like what's been said there on the slide, it is a reason but it's not the only reason.

If you don't turn up to an activity and you haven't drank enough, it's highly likely that you will be dehydrated.

However, you could be someone that turns up and have drunk enough fluids but you then sweat a lot, or the intensity of your training is really high, or the environment you're working in or training in is also quite a hot one.

And all of those reasons can actually cause dehydration.

So remember I said about that impair and that hindering of performance? Look what Jacob's been told here.

"The coach continually tells us "that dehydration can cause a 20% decrease in performance.

"Is that true?" And I can understand why he's asking that 'cause 20% feels like quite a high percentage in the grand scheme of things when you're trying to work as best you can to 100%.

And it is a very much go-to figure with lots of studies that have been conducted around lack of hydration, knowing that there is that real significant impair of performance by some of that loss of functioning.

So let's look at those consequences.

We've got some images here that reflect some of the consequences that can happen as a result of not having that sufficient amount of water.

The first one is looking at those blood cells.

They all look very kind of close to each other and connected.

And what they're trying to represent is that blood becomes thicker.

Now, if you haven't got enough water in your body, what it does is it chooses to take the fluid from the plasma, and the plasma in your blood is what keeps your blood nice and thin and allows it to move through the body or around the body smoothly.

If you take that water from that plasma, as a result, you get that thicker blood.

Remember, our keyword for that is viscosity.

So you get an increase in blood viscosity, that means it's thick, it's stickier, and, as a result, it's not gonna move around the body well and probably be much slower in terms of the flow.

Now, a direct impact of that is, your heart is gonna have to work a lot harder.

So you've learnt lots over this course around heart rate and some of those typical values.

As a result of that blood being very sticky and thick, your heart will increase, and that's going to mean that you're probably gonna fatigue much earlier than maybe you wouldn't if that blood flow was nice and thin and moving well around the body.

And we've explored this bit about temperature when we were talking about sweating to cool down.

If you aren't able to do that, that body temperature is going to increase, and even a couple of degrees above that normal body temperature can mean that you're at risk of overheating.

And if we aren't taking on that water to cool that body down, that could be one of those consequences.

Now, we have another three images here.

Could you maybe think or pause the recording and consider what they might represent? That first image, as you can see there's been some time in there, your reaction time gets much slower as a result of being dehydrated.

I'm sure you could all sit here and think of sports where that can have real consequences if you aren't reacting as quick as you used to or your decisions are much slower or poorer because you aren't able to respond well to that stimuli.

And that last image looks to me like that individual is maybe feeling a little bit of tiredness or fatigue in the muscles.

Potentially that could be from cramp.

We don't know if that's 'cause she's dehydrated, however, we do know that is a consequence of being dehydrated.

So which of these is not a consequence of dehydration? Is it A, that viscous blood? Is it B, an increase in reaction time? Is it C, poorer decision making? Or, finally, you get an increase in that heart rate and body temperature? Five seconds to decide.

Well done if you noticed that it actually is B, increased reaction time.

If you have an increase in reaction time, that means it's getting better, it's faster.

Whereas we're saying that this will not be the case, those reactions will be slower.

So you'll get that decreased reaction time, and that's not a consequence of dehydration.

Now, there are lots of consequences to remember here, so I'm going to share with you the acronym THIRST.

Now, that works well, doesn't it? If you think, often, if you're dehydrated, you are going to feel thirsty, your body's going to want to consume more water.

Now, what THIRST allows us to do is just memorise or remember those consequences that we've just explored.

So that T, remember we said about the blood getting thicker, you're getting that increased blood viscosity.

That heart rate will increase.

You'll get increased body temperature.

Those reactions are slower, and we know that can lead to that poorer decision making.

That S links to that muscles feeling sore or getting those cramps.

And also that tiredness, which we like to use that correct word of fatigue.

Now, with THIRST being a key acronym for you, we're gonna go onto our first task, and this is divided into two parts.

The first time is to define dehydration, hydration.

And once you've done that, think about four reasons why an athlete needs to rehydrate when they're playing sport to prevent those consequences of dehydration.

Pause the recording and come back to me when you're ready.

Welcome back.

Did you, for dehydration and hydration, think back to our keywords? So knowing that dehydration is the excessive loss of body water, and, as a result of that, the function of the body is interrupted.

Whereas hydration is a state where we have that sufficient amount of water, so our functioning is normal and at its very best.

And then for that second part, there are many of these that you could have chosen, particularly if you'd used THIRST, which was a key part to this task.

But you could have said, in terms of your description, that one of those reasons is so that blood is flowing freely.

We don't want that to be slow because of that increased blood viscosity.

You don't want that early fatigue, so it's preventing that increased heart rate.

You definitely want to be on your very best in terms of your decision making.

Got a nice word there of optimal.

We don't want that to be poor, we don't want that to be slower.

And it could be that you really don't want to have that feeling of overheating 'cause that's not a very pleasant feeling and one that's gonna have to probably mean that you might have to stop if you are starting to overheat.

So that takes us onto our second part of our lesson.

We've looked at those effects or those consequences, and now we're gonna develop our skill of evaluation.

So really unpicking that impact, particularly when you play sport.

So I'm gonna introduce you to Laura.

Whereas Jacob was a squash player, Laura is a rugby player, and she's sharing with us here that she likes THIRST.

That has really allowed her to have a memorable way of remembering those reasons as to why she doesn't want to be dehydrated, particularly when she's at training, particularly when she's playing.

Now, what Laura might do is might get asked to evaluate those consequences.

So doing that kind of next level skill.

So just a reminder here that, when we evaluate, we are making a judgement from available evidence.

So that judgement is on that consequence for that specific sport.

So Laura's just checking in here and saying, okay, so that's her using evidence from rugby and hydration to provide a judgement on why dehydration has those consequences.

Yes, Laura, that's really good.

You're looking at what the evidence is.

It's you knowing rugby but also you know the importance of hydration, and making that judgement about how that consequence is not a good thing when you are playing sport.

So the key to what I've just shared with you there is that say why.

When we evaluate, we really do link our kind of thinking and our skills to that opinion and that say why.

Now, what Laura could do is use a really simple approach of what why this leads to.

So by that I mean, she might kind of consider the what in terms of evidence from rugby.

So it could be that, as she's playing, if she's in that dehydrated states, her tackles are likely to be not as good or certainly maybe late or mistimed.

So that's the what.

Now, the why links us back to THIRST.

Well, one of the reasons why in terms of what we've already learnt about is those reaction times are going to be slower.

And to really make that a judgement and make that kind of clear in terms of the impact, what is that gonna lead to? Well, for Laura, if she is mistiming those tackles, those opponents are gonna, one, be free of that tackle or break that tackle and then have possession of the ball.

So we can see there how we've got judgement shown just by following that what, why, which leads to model.

So let's have a little go of this together.

We've got Laura saying here that her muscles, when she's playing, were feeling very heavy and tired.

Why is that from THIRST? Exactly, that was the S and the T, those sore muscles and that muscle fatigue, those tired muscles.

What's that gonna lead to in rugby? What's gonna be the impact of that? Now, what you could have said is that if they are feeling that fatigue, they're not gonna be able to keep up with those phases of play or they're definitely gonna be in the wrong position as a result of that.

And, you know, you can see there we've got an example of their not being in that correct defensive position.

So here's our acronym again, and what we've kind of got modelled to us there on those previous two slides is that use of the R, the S, and the T.

So if we needed to consider the T, the H, and the I, how would we evaluate those for Laura in rugby? What you might want to do here is just pause the recording and have a go at this yourself.

Maybe consider how you would do that what, why, which leads to approach to help you practise that skill of evaluation.

And just do it three times, once for that thicker blood, secondly, for the increase in heart rate, and, finally, for that increase in body temperature.

Now, if we were going for the T, that thicker blood, we know that that definitely means that there's that slow blood flow.

So that oxygen is not going to be going around that body as quickly as it normally is.

So that cardiovascular endurance or that aerobic respiration will be lower.

She's gonna feel those effects of fatigue earlier.

It could be that the passing is not as good as it was and that what that will lead to is, you know, that pass not getting to her teammate.

The heart rate increasing might lead to that early anaerobic respiration.

We've learnt that anaerobic respiration leads to that buildup of lactic acid.

So that's gonna happen earlier.

Means that, you know, as a result she might not be able to run as quickly or be able to sprint towards the ball.

And, finally, if she's overheating, it might be that that what is that she really has that loss of focus and concentration, maybe at a lineout, and that if she jumps too early, what that leads to is you're gonna really lose that possession of the ball.

You can see there how our really simple THIRST acronym is allowing us to develop that skill of making a judgement in terms of these consequences.

So let's revisit Jacob and squash, and which of these statements is Josh actually doing correct evaluation of increased reaction time in his sport of squash? Is it A, that his legs felt achy and he wasn't quick enough to reach the ball? Is it B, that he was too slow to respond to the ball bouncing off the wall and therefore couldn't make the next shot? Or is it C, that he was really aware that his heart was racing towards the end of the set and, as a result, he lost focus? Five seconds to decide.

Absolutely, well done, it's B.

Because we can see Jacob is talking about that inability or that slower response to that stimulus, which is that ball bouncing off the wall and maybe then not being able to make that next shot.

So if we develop that further for our what, why, and which leads to for Jacob, the what, I'm too slow to respond to the ball bouncing off the wall, why, that slower reaction time.

What does that lead to? Well, if you're not gonna get to the ball and make that shot, quite simply, the impact is that point will go to the opponent and it will be a loss for Jacob.

Which leads us onto our final task of the lesson.

We've got three sports here.

We've got football, we have dance, and we have badminton.

So all quite different in terms of their demands.

What I would like you to do is evaluate two consequences of dehydration for each of those sports.

And if you can, 'cause we've modelled it well, you use the what, why, which leads to approach to help you make that judgement.

Pause the recording and come back to me when you're ready.

Welcome back.

How did you all do? Now, I know it will have been really determined on which of the consequences you used from THIRST.

We have some examples here that you can use to look at your examples just to kind of check that what, why, which leads to approach.

So an example there of football, which is where the what is, the pass is not strong enough.

The why, the fatigue in muscles.

Which leads to potentially the opposition intercepting the ball.

We've got an example there from tackles, which we've previously seen for rugby.

For dance, we've got a slightly different approach.

That first one is again linking to those muscle cramps.

But then that second one is that increased heart rate from that higher blood viscosity.

Just make note of the which leads to.

We've gotta remember to quote the obvious.

So if you can't hold that balance in dance, you might get a lower score.

That's good judgement.

You're judging from that available evidence of both the consequence and the sport.

Likewise, if you aren't able to get that leap, you might be off time with the music and that could also lead to a lower score.

And, finally, for badminton it could be that you picked up on that slower decision making or those slower reactions which lead to that poor decision making.

Again, you can see the what in terms of the net shot, the why, and then which leads to.

And we've got that finally for the serve, which could be from that loss of focus and concentration when you're feeling too hot or potentially overheating.

So in terms of our summary, we know now, probably more so than we did at the start, that that water balance is really important for hydration.

So that when our body's functioning, it's functioning well but more so during sport and physical activity 'cause you really need to reduce that likelihood of dehydration.

We've learnt there are many consequences to dehydration.

We spoke about how that can really impair performance.

And we use that acronym of THIRST to remind ourselves of what those consequences are.

Quick reminder there we've got that slow blood flow, that increased heart rate and body temperature, slower reactions, poorer decision making, and also that impact on muscles in terms of cramp and fatigue.

And our final outcome of that is probably acknowledging that rehydration is therefore crucial before we go to sport but more so during and after.

So taking on that water and those fluids whilst you're training and playing but also as part of that recovery, making sure you restore that water lost so you're not feeling those consequences.

I have really enjoyed taking you through hydration and trying to avoid those consequences of dehydration, and I look forward to working with you on the next lesson.