0:00:08 > 0:00:11I kayaked 2,000 miles along the Amazon.
0:00:17 > 0:00:20I walked a high wire between the chimneys
0:00:20 > 0:00:23at Battersea Power Station.
0:00:25 > 0:00:28And this time around, I'm going to be taking on
0:00:28 > 0:00:31my most physically demanding challenge to date.
0:00:38 > 0:00:41I will be attempting to get to the South Pole
0:00:41 > 0:00:45entirely under my own steam and taking everything I need with me.
0:00:45 > 0:00:48I will be walking, kite-skiing, and in a world first
0:00:48 > 0:00:53trying to cycle part of my route to the Pole.
0:00:53 > 0:00:55It's the coldest and windiest place on earth,
0:00:55 > 0:00:59temperatures drop to as low as minus 50 degrees Celsius.
0:00:59 > 0:01:02I have no idea how people do this. Honestly.
0:01:02 > 0:01:05SHE CRIES OUT
0:01:11 > 0:01:15I don't want to play any more, this is so frustrating.
0:01:29 > 0:01:32On today's programme, Helen starts to prepare
0:01:32 > 0:01:35for her epic 500-mile journey to the South Pole for Sport Relief.
0:01:37 > 0:01:41- You deep body temperature is now 36.5.- How long left?
0:01:41 > 0:01:44She travels to Sierra Leone to find out how Sport Relief
0:01:44 > 0:01:48can stop dirty water killing thousands of people every year.
0:01:48 > 0:01:52If you fell in there, well, I dread to imagine. It's not even covered.
0:01:52 > 0:01:54But he knows he needs the water.
0:01:54 > 0:01:56And the world's greatest living explorer
0:01:56 > 0:01:59delivers a chilling warning.
0:01:59 > 0:02:01If you allow your hands and your feet
0:02:01 > 0:02:03to get to a certain temperature,
0:02:03 > 0:02:07the blood will freeze and that flesh will die.
0:02:07 > 0:02:10I made a mistake for three minutes, that was too much.
0:02:12 > 0:02:16Helen's got just five months to prepare for the South Pole.
0:02:16 > 0:02:19But before she can start training, she needs a medical
0:02:19 > 0:02:23to make sure she's even allowed to take on her Polar Challenge.
0:02:23 > 0:02:26There is no getting away from the fact that this is epic.
0:02:26 > 0:02:29This is potentially the biggest thing I will ever take on.
0:02:29 > 0:02:33In my head, I am telling myself that this medical is not a big deal
0:02:33 > 0:02:35and it's all going to be fine, but it is a big deal
0:02:35 > 0:02:39because if I don't pass it, I won't not be allowed to go.
0:02:39 > 0:02:42This adventure will be over before it has even begun.
0:02:44 > 0:02:45Professor Greg Whyte is the expert
0:02:45 > 0:02:48who will give Helen the all clear... or not.
0:02:48 > 0:02:50He specialises in endurance
0:02:50 > 0:02:53and has trained celebrities such as Ferne Cotton...
0:02:53 > 0:02:58- Level 20!- ..and David Walliams for their Sport Relief challenges.
0:02:59 > 0:03:01Greg's under no illusions just how tough
0:03:01 > 0:03:03Helen's Polar Challenge will be.
0:03:03 > 0:03:06Helen has run across the desert, she has canoed down the Amazon,
0:03:06 > 0:03:09but this will be the toughest challenge she has ever faced.
0:03:12 > 0:03:14How hard do you think it's going to be?
0:03:14 > 0:03:18Antarctica is brutal, in a word.
0:03:18 > 0:03:22It's one of the toughest places on the planet.
0:03:22 > 0:03:25In the summer when it is 24 hours' daylight,
0:03:25 > 0:03:27temperatures still get down
0:03:27 > 0:03:29in the region of minus 60 on certain days.
0:03:31 > 0:03:34These are very, very tough places, and in fact
0:03:34 > 0:03:36very dangerous places to be.
0:03:36 > 0:03:38There's lots of things that can happen.
0:03:38 > 0:03:41Frostbite, which can happen in minutes.
0:03:41 > 0:03:46You can lose digits, particularly fingers, toes, nose and ears.
0:03:46 > 0:03:48The cold is really potent.
0:03:48 > 0:03:52What we know is that things like heart attacks rise in cold weather.
0:03:52 > 0:03:54- I couldn't have a heart attack? - Possibly.
0:03:54 > 0:03:58The key thing to remember is that the cold kills.
0:03:58 > 0:04:00This is how serious this challenge is.
0:04:00 > 0:04:03This is an incredibly difficult environment to deal with
0:04:03 > 0:04:07and the cold can have incredibly profound affects on your body.
0:04:07 > 0:04:10There's no point doing it, if there's going to be a problem.
0:04:10 > 0:04:15- I don't know why I'm smiling. - Nor do I.- It'll be fine!
0:04:15 > 0:04:18And to find out if there are any problems,
0:04:18 > 0:04:20Greg takes a reading of Helen's heart rate
0:04:20 > 0:04:24while she's resting before putting her to work on an exercise bike.
0:04:25 > 0:04:28- Take a seat on there for me, Helen. - OK.- Lovely.
0:04:28 > 0:04:33- What is this testing? - This is the torture chamber. OK?
0:04:33 > 0:04:36We are doing two things here, really.
0:04:36 > 0:04:39One is that we're looking at the heart and how the heart is working.
0:04:39 > 0:04:42Particularly how it's working under stress.
0:04:42 > 0:04:45So we're basically going to look at the heart with this.
0:04:45 > 0:04:48As the exercise gets harder and harder, and harder,
0:04:48 > 0:04:50the heart has to work harder and harder
0:04:50 > 0:04:52and we're going to see how it's coping with that.
0:04:55 > 0:04:59She's off and it's not long before Helen's feeling the effects.
0:04:59 > 0:05:02I think the important thing here is that, when you
0:05:02 > 0:05:04were lying down, your heart rate was 47 beats per minute?
0:05:04 > 0:05:08- Now, at 102 beats per minute. - Already?!
0:05:10 > 0:05:14Helen's heart rate has doubled with just a little bit of exercise
0:05:14 > 0:05:17so Greg is keen to see how she performs
0:05:17 > 0:05:19when she's pushed to the limit.
0:05:19 > 0:05:23Keep that power up, keep working, not long to go. Keep working.
0:05:23 > 0:05:27Keep pushing it out, really drive it. Really drive it.
0:05:27 > 0:05:31Push loads, come on! Keep driving, don't give up.
0:05:31 > 0:05:36Keep driving, keep driving! Drive those legs around. Drive them round.
0:05:36 > 0:05:40Everything you've got, everything, everything, everything.
0:05:40 > 0:05:44Good stuff. And stop there. Very nice, indeed.
0:05:44 > 0:05:47Well done. Well done. Excellent work.
0:05:47 > 0:05:49After a hard slog, it's the moment of truth...
0:05:49 > 0:05:53Will Greg have found any medical problems that will stop Helen
0:05:53 > 0:05:55from taking on her Polar Challenge?
0:05:55 > 0:05:58- Have I passed?- Yes, is the very simple answer to that.
0:05:58 > 0:06:02What I was interested in, from a health perspective,
0:06:02 > 0:06:05is how the heart and lungs can cope with very hard exercise
0:06:05 > 0:06:07and that was perfectly normal.
0:06:07 > 0:06:09I've done what you expected,
0:06:09 > 0:06:13but I'm not necessarily fit enough to get to the South Pole on a bike.
0:06:13 > 0:06:15To get you to one of the most
0:06:15 > 0:06:17inhospitable places on the planet,
0:06:17 > 0:06:20and have you work as hard as you can on a bike, we have a way to go.
0:06:23 > 0:06:27Some of the greatest explorers have crumbled in Antarctica.
0:06:27 > 0:06:30This is not about being fit, this is not about having experience.
0:06:30 > 0:06:33This is a really, really difficult challenge.
0:06:35 > 0:06:39Helen is travelling to the coldest, windiest, driest place on earth.
0:06:39 > 0:06:44Temperatures regularly fall to minus 50 degrees Celsius.
0:06:44 > 0:06:48That's at least twice as cold as your freezer at home!
0:06:48 > 0:06:51To survive, she'll carry all her food and equipment on a sled
0:06:51 > 0:06:53which will be incredibly physically demanding.
0:06:53 > 0:06:57Fully packed, Helen's sled will weigh 82 kilograms,
0:06:57 > 0:07:00the same as dragging along a fully grown man.
0:07:01 > 0:07:04Greg's next test is to see how fast Helen can pull the sled
0:07:04 > 0:07:07over a distance of ten metres.
0:07:07 > 0:07:10There's lot of force going through that back and shoulders, OK?
0:07:10 > 0:07:12- OK.- Two, one, go.
0:07:13 > 0:07:16That's good, that's good, that's good.
0:07:16 > 0:07:19That's really quite nice.
0:07:21 > 0:07:23That is it. Good, and push.
0:07:23 > 0:07:26- Oh, my Lord. - Ten metres now, that's it.
0:07:26 > 0:07:30Keep pushing, keep pushing. Keep working, keep working.
0:07:32 > 0:07:35Touch the wall.
0:07:35 > 0:07:38Beautiful. 18 seconds.
0:07:38 > 0:07:41500 miles, are you having a laugh?!
0:07:41 > 0:07:45That was 18 seconds for ten metres.
0:07:45 > 0:07:48'I'm not fit enough and I'm not strong enough yet,'
0:07:48 > 0:07:52but I believe with a lot of training and hard work, I'll get there.
0:07:52 > 0:07:54It's not going to be fun, the training,
0:07:54 > 0:07:56and I know I'm not going to enjoy it.
0:07:56 > 0:07:59I know there'll be days when I think, "Why am I doing this?"
0:07:59 > 0:08:01But I'm doing this for a good cause.
0:08:01 > 0:08:02I'm doing it for Sport Relief,
0:08:02 > 0:08:04I'm doing it for projects I believe in
0:08:04 > 0:08:07and because I have met children whose lives are transformed
0:08:07 > 0:08:09by Sport Relief projects.
0:08:09 > 0:08:13Children from countries like Sierra Leone in West Africa.
0:08:25 > 0:08:29The country has been struggling to recover from a decade of conflict,
0:08:29 > 0:08:32but now thousands of people a year are dying from a problem
0:08:32 > 0:08:35much easier to solve than the civil war...
0:08:35 > 0:08:36Dirty water.
0:08:40 > 0:08:43Diarrhoea caused by drinking dirty water
0:08:43 > 0:08:46is one of the biggest causes of death in Sierra Leone.
0:08:48 > 0:08:52Infections and parasites cause cholera and dysentery.
0:08:52 > 0:08:55And monsoon floods spread contaminated water
0:08:55 > 0:08:58that fill up the wells with sewage and chemicals.
0:08:58 > 0:09:01One boy who knows all about the devastating effects
0:09:01 > 0:09:05that contaminated drinking water can have on a family is Issa.
0:09:07 > 0:09:09Helen went to Calaba Town
0:09:09 > 0:09:13where he introduced her to his Dad and grandmother
0:09:13 > 0:09:16and showed her their house.
0:09:16 > 0:09:20I lost my mum, my eldest sister and my younger brother.
0:09:23 > 0:09:27All three died from drinking dirty water.
0:09:27 > 0:09:32- Your brother and mum got sick because they drank water from the well?- Yes.
0:09:32 > 0:09:34The contaminated well that they drank from
0:09:34 > 0:09:37is just a few metres from Issa's front door.
0:09:39 > 0:09:42What do you think about this well being right here?
0:09:42 > 0:09:46I think about it, it is not good. It is dangerous.
0:09:46 > 0:09:49Everybody that drinks get ill.
0:09:49 > 0:09:52Your mum and brother drank from it, why?
0:09:52 > 0:09:55Because there is no other water to drink here.
0:09:55 > 0:10:01It's hard for Helen to believe that something we all take for granted...
0:10:01 > 0:10:05a drink of water, killed Issa's mum. He misses her dreadfully.
0:10:05 > 0:10:09Sometimes when I think of her, I sit at the corner and cry.
0:10:11 > 0:10:14- I'm sure she would be very proud of you.- Yes.
0:10:21 > 0:10:26Can you imagine something killing your mum or your baby brother,
0:10:26 > 0:10:29and having to look at it every single day.
0:10:29 > 0:10:31That's exactly what he does
0:10:31 > 0:10:35and he does it with very little quarrel or complaint.
0:10:37 > 0:10:40The only way Issa and the remaining members of his family
0:10:40 > 0:10:44can get clean water is to walk to the nearest safe well.
0:10:44 > 0:10:46Helen goes with him on the long journey.
0:10:46 > 0:10:51In the dry season, how many times a week do you go to the well?
0:10:51 > 0:10:54Always in the morning, 5 o'clock before I go to school.
0:10:54 > 0:10:57- Do you mind going? - It is hard work.
0:11:02 > 0:11:05Not only does Issa have to walk for two hours
0:11:05 > 0:11:08to get clean water back to his family,
0:11:08 > 0:11:10but he also has to cross the busy and dangerous main road.
0:11:13 > 0:11:16When they eventually get to the well,
0:11:16 > 0:11:20Helen see's it really isn't a place for a 12-year-old boy.
0:11:20 > 0:11:23Oh, my word. If you fell in there, well, I dread to imagine.
0:11:23 > 0:11:26It's not even covered.
0:11:26 > 0:11:28But he knows he needs the water.
0:11:28 > 0:11:33He's well over an hour away from safe water,
0:11:33 > 0:11:36not even running water, just water that is safe enough to drink.
0:11:36 > 0:11:41And then they do the same hour-long journey in reverse,
0:11:41 > 0:11:44but this time with heavy buckets of precious, clean water.
0:11:44 > 0:11:47Oh, my Lord, oh, my Lord.
0:11:47 > 0:11:50Oh, my word.
0:11:50 > 0:11:54I'm definitely not putting it on my head.
0:11:56 > 0:11:58I couldn't carry this every day.
0:12:03 > 0:12:07They've only been going for a few minutes
0:12:07 > 0:12:09when Issa suddenly cuts his foot.
0:12:10 > 0:12:13OK? Oh, Issa.
0:12:13 > 0:12:18The pressure of what he has to do every single day is taking its toll.
0:12:18 > 0:12:21If he doesn't go home with the water,
0:12:21 > 0:12:23then his family won't drink.
0:12:23 > 0:12:28His one-year-old brother won't get a drink of water.
0:12:28 > 0:12:30Why don't you get on my back.
0:12:30 > 0:12:34I'll take you, then we'll come back for the water.
0:12:38 > 0:12:39Helen can help him today,
0:12:39 > 0:12:43but tomorrow Issa will set out on his own again.
0:12:43 > 0:12:46That's why Issa and thousands of children like him
0:12:46 > 0:12:51need your support to help raise money for Sport Relief this year.
0:12:56 > 0:12:59This is kind of annoying, in this day and age
0:12:59 > 0:13:04something so simple, and something so easily sorted hasn't been.
0:13:04 > 0:13:09But that is what you and I can do by getting involved with Sport Relief.
0:13:14 > 0:13:18Just a few miles away, people are already seeing the benefits
0:13:18 > 0:13:19of a Sport Relief project
0:13:19 > 0:13:23which has brought clean water back to the community.
0:13:27 > 0:13:30Just over here is a brand new well.
0:13:30 > 0:13:33It's so new that the concrete is still drying on it.
0:13:33 > 0:13:35It's on the other side of town from Issa,
0:13:35 > 0:13:38but if you want to make sure Issa and other kids like him
0:13:38 > 0:13:41can drink safe, clean drinking water from wells like this
0:13:41 > 0:13:44then all you need to do is get involved with Sport Relief this year.
0:13:44 > 0:13:46bbc.co.uk/sportrelief.
0:13:46 > 0:13:49THEY ALL CHEER
0:13:51 > 0:13:54Visiting Sierra Leone has made Helen all the more determined
0:13:54 > 0:13:59to succeed with her Polar Challenge for Sport Relief.
0:14:03 > 0:14:06To help her prepare for the brutal conditions of Antarctica,
0:14:06 > 0:14:09Helen wants to find out first-hand what it's like
0:14:09 > 0:14:11from someone who has been there and done it.
0:14:11 > 0:14:14So she's off to meet the man described as the world's
0:14:14 > 0:14:17greatest living explorer, Sir Ranulph Fiennes.
0:14:19 > 0:14:23He was the first person to cross the Antarctic and Arctic Oceans.
0:14:25 > 0:14:29He's the oldest Briton ever to have reached the summit of Everest
0:14:29 > 0:14:33and was the first person to reach both the North and South Poles.
0:14:35 > 0:14:38Helen's already found out how hard it is to pull a heavy sled
0:14:38 > 0:14:41over ten metres on flat ground,
0:14:41 > 0:14:45but her route to the South Pole won't be quite that simple.
0:14:45 > 0:14:49She'll travel over all sorts of uneven surfaces in Antarctica.
0:14:49 > 0:14:52To help her learn the techniques she needs,
0:14:52 > 0:14:56Sir Ranulph is putting Helen through her paces - tyre pulling.
0:14:56 > 0:14:59The tyres behave in the same way as a heavy sled,
0:14:59 > 0:15:03weighing Helen down and getting stuck in all the wrong places!
0:15:03 > 0:15:05- It's not too bad.- Right.
0:15:08 > 0:15:10Oh, that's definitely heavier.
0:15:10 > 0:15:13Because I'm in front of you, I feel I should pick that one.
0:15:13 > 0:15:15- Maybe you ought to start with that one.- OK.
0:15:17 > 0:15:19Concentrate, Helen, this is a man
0:15:19 > 0:15:22who's conquered the North and South Poles.
0:15:22 > 0:15:24No pressure then!
0:15:24 > 0:15:27This is a bit embarrassing. It's so heavy.
0:15:27 > 0:15:29The backs of my legs are already burning.
0:15:31 > 0:15:33Are you ready to try the logs?
0:15:33 > 0:15:36They are the nearest thing we can simulate
0:15:36 > 0:15:39in these circumstances for the Sastrugi.
0:15:40 > 0:15:43Sastrugi is the name for an unusual snow formation
0:15:43 > 0:15:46that Helen will encounter in the Antarctic.
0:15:46 > 0:15:49The long wave-like ridges of snow are caused by wind
0:15:49 > 0:15:51eroding the snow from one side.
0:15:51 > 0:15:56They're rock hard and very difficult to cross with a heavy sled.
0:15:56 > 0:16:00The stronger Helen is, the better she'll be able to deal with them.
0:16:02 > 0:16:04If you're pulling and it won't come,
0:16:04 > 0:16:07don't keep trying too often because your energy gets exhausted.
0:16:07 > 0:16:11So quickly turn round and learn the high jinx like haul to the left,
0:16:11 > 0:16:15haul to the right, put your body down, then come up like that.
0:16:15 > 0:16:17That's it, that's it. Keep pulling.
0:16:17 > 0:16:21You really do want to keep changing things to suit yourself.
0:16:22 > 0:16:24That's good. Sideways. Excellent.
0:16:28 > 0:16:30- Yeah!- No, first class.
0:16:34 > 0:16:39Having done little things like Sastrugi and pressure ridges,
0:16:39 > 0:16:41we need to give you a bit more incline,
0:16:41 > 0:16:43- so if we head down the valley...- OK.
0:16:45 > 0:16:46This looks steep.
0:16:51 > 0:16:54Try it as much as you possibly can
0:16:54 > 0:16:58and the moment you think you're not winning, turn round.
0:17:00 > 0:17:01Oops a daisy.
0:17:01 > 0:17:05In cravass fields, falling around isn't always advisable.
0:17:06 > 0:17:10I had no idea that the terrain would be that extreme
0:17:10 > 0:17:13and I didn't really entertain the idea that my sledge
0:17:13 > 0:17:16would catch on things, jar and pull me back.
0:17:16 > 0:17:19I'm glad that I've got a better idea of what the terrain
0:17:19 > 0:17:21is going to be like. It does mean that I'm going to have
0:17:21 > 0:17:24to look at my modes of transport a bit more carefully.
0:17:26 > 0:17:27I'm impressed by Helen.
0:17:27 > 0:17:29She loves to do that little bit extra.
0:17:29 > 0:17:33You can see it's a personal affront not to finish whatever it is.
0:17:33 > 0:17:35But being physically strong
0:17:35 > 0:17:38isn't the only skill Helen will need in the Antarctic.
0:17:38 > 0:17:41Attention to detail is vital.
0:17:41 > 0:17:45In temperatures of minus 50, simple mistakes can lead to frostbite,
0:17:45 > 0:17:48something that Sir Ranulph knows all too well.
0:17:50 > 0:17:56If you allow your flesh anywhere but normally your hands and your feet,
0:17:56 > 0:17:59to get to a certain temperature, the blood will freeze,
0:17:59 > 0:18:03the quicker you will get frostbite and that flesh will die,
0:18:03 > 0:18:05starting usually at the ends
0:18:05 > 0:18:08and coming down towards the hands or the toes.
0:18:08 > 0:18:10What happened with your fingers?
0:18:12 > 0:18:16That was in water, at night. It was minus 45, minus 48.
0:18:16 > 0:18:20I went over ice that was collapsing and my sledge fell in the water.
0:18:20 > 0:18:23It dragged me down ten feet.
0:18:23 > 0:18:26Once the sledge was in the water, jammed under the ice blocks,
0:18:26 > 0:18:30it had my tent and my cooker so I had to get it out, which meant
0:18:30 > 0:18:32putting my hand under the water.
0:18:32 > 0:18:37I lost all the ends of those fingers in only three minutes
0:18:37 > 0:18:39of being exposed to the wind
0:18:39 > 0:18:43and the cold with no insulation to protect them.
0:18:45 > 0:18:48Even people with vast amount of experience do get caught out
0:18:48 > 0:18:51and ultimately do fail, don't they?
0:18:51 > 0:18:54Do I need to worry because I'm a complete novice?
0:18:54 > 0:18:57In 38 years of doing polar expeditions,
0:18:57 > 0:19:01I made a mistake for three minutes and that was too much.
0:19:02 > 0:19:05Meeting Sir Ranulph Fiennes has given Helen a taste of just
0:19:05 > 0:19:08how punishing the extreme cold of Antarctica can be,
0:19:08 > 0:19:12but she's still keen to find out more.
0:19:14 > 0:19:17100 years ago another great British explorer,
0:19:17 > 0:19:20Captain Robert Falcon Scott led a team attempting to be
0:19:20 > 0:19:22the first people to reach the South Pole.
0:19:24 > 0:19:28Pulling all their food and equipment on sleds, their aim was to beat
0:19:28 > 0:19:32a rival expedition led by Norwegian explorer Roald Amundsen.
0:19:36 > 0:19:41Helen has come to the British Film Institute to watch a rare film made
0:19:41 > 0:19:45at the time of Scott's expedition by a filmmaker called Herbert Ponting.
0:19:45 > 0:19:49It gives a real insight into what the very first
0:19:49 > 0:19:51South Pole explorers had to face.
0:19:52 > 0:19:55Bryony Dixon is one of the experts who's been restoring the film
0:19:55 > 0:19:59for the past two years and knows the story inside out.
0:20:05 > 0:20:08So they must have had no idea
0:20:08 > 0:20:11what they were going to and no idea what to expect.
0:20:12 > 0:20:14As it says, only ten human beings
0:20:14 > 0:20:19had ever trodden on that bit of land, in the world ever.
0:20:19 > 0:20:23No-one had any idea what was in the interior Antarctica.
0:20:24 > 0:20:26On the 1st November 1911,
0:20:26 > 0:20:30Captain Scott, Edward Wilson, Henry Bowers, Lawrence Oates
0:20:30 > 0:20:35and Edgar Evans set out on their 850-mile journey to the South Pole.
0:20:35 > 0:20:38Their goal, to be the first people ever to get there.
0:20:40 > 0:20:43But Scott and his team weren't the only ones with that ambition.
0:20:43 > 0:20:46A Norwegian Captain, Roald Amundsen,
0:20:46 > 0:20:48had also landed a team in Antarctica.
0:20:48 > 0:20:50The race to the Pole was on!
0:20:51 > 0:20:56What he didn't know was Amundsen had picked a better route.
0:20:56 > 0:20:57It was shorter, more direct
0:20:57 > 0:21:03and it didn't have to go up this huge glacier, the Beardmore glacier.
0:21:03 > 0:21:07Travelling with Scott were four support parties.
0:21:07 > 0:21:10Their job was to drop off large quantities of food
0:21:10 > 0:21:12at designated points along the route which Scott
0:21:12 > 0:21:15and his men would use on their return journey.
0:21:15 > 0:21:17There's no food in Antarctica at all
0:21:17 > 0:21:21so you've got to take everything you need with you.
0:21:22 > 0:21:25Once the last of the support parties had turned back,
0:21:25 > 0:21:27Scott and his companions were left all alone
0:21:27 > 0:21:29to cross the great ice desert.
0:21:31 > 0:21:36After 78 days, exhausted, frozen and starving,
0:21:36 > 0:21:39Scott and his men finally reached the South Pole
0:21:39 > 0:21:42on the 17th January 1912.
0:21:42 > 0:21:45It should have been the greatest moment of their lives.
0:21:45 > 0:21:49But to their dismay they found a small, deserted tent
0:21:49 > 0:21:52and the Norwegian flag flying.
0:21:53 > 0:21:57Roald Amundsen had beaten Scott to the pole by just 33 days.
0:21:57 > 0:22:01Shattered by the news, he wrote in his diary:
0:22:10 > 0:22:15Devastated, the team now had to face the gruelling return journey
0:22:15 > 0:22:17850 miles back to base camp.
0:22:22 > 0:22:27Even if they'd had enough food, and the conditions has been better,
0:22:27 > 0:22:28they may not have survived.
0:22:28 > 0:22:32On the 17th February, the first man died.
0:22:32 > 0:22:36Edgar Evans fell into a coma and never woke up.
0:22:36 > 0:22:38Next to fall was Captain Oates.
0:22:38 > 0:22:40Suffering from terrible frostbite,
0:22:40 > 0:22:42he was afraid of holding up his companions.
0:22:42 > 0:22:44He left the tent one night saying,
0:22:44 > 0:22:48"I'm just going outside, and I may be some time."
0:22:48 > 0:22:50They never saw him again.
0:22:51 > 0:22:54Weak and running desperately low on food, Scott and his men
0:22:54 > 0:22:58were trapped by a storm in their tent for five days.
0:22:58 > 0:23:02This is the really tragic, tragic bit,
0:23:02 > 0:23:06they got within 11 miles of the food depot.
0:23:06 > 0:23:08It was one day's march.
0:23:08 > 0:23:12- After all that! - And they just couldn't do it.
0:23:12 > 0:23:15On Thursday 29th March, Scott wrote,
0:23:15 > 0:23:19"It seems a pity but I do not think I can write any more."
0:23:20 > 0:23:25Beaten by the freezing temperatures of Antarctica one by one,
0:23:25 > 0:23:27the men died where they lay.
0:23:29 > 0:23:32Although Captain Scott's expedition ended in tragedy, the bravery,
0:23:32 > 0:23:35sense of adventure and determination shown by the men
0:23:35 > 0:23:40has inspired generations of explorers, including Helen.
0:23:40 > 0:23:44But unlike Scott, she has the advantage of modern day technology.
0:23:44 > 0:23:48It will help her prepare to face the biggest enemy to polar explorers,
0:23:48 > 0:23:50the extreme cold.
0:23:54 > 0:23:56She's come to the University of Portsmouth
0:23:56 > 0:23:59to meet Professor Mike Tipton and his team
0:23:59 > 0:24:02and take part in an experiment to see how her body reacts to the cold.
0:24:02 > 0:24:04What?
0:24:08 > 0:24:12Here we go then, in five, four, three,
0:24:12 > 0:24:14two, one... Go!
0:24:16 > 0:24:18Oh, it's really cold! Ah!
0:24:20 > 0:24:22Just relax, that's fine.
0:24:24 > 0:24:26Just stick with it.
0:24:26 > 0:24:29At 12 degrees Celsius and with no special clothing to protect her,
0:24:29 > 0:24:32Helen's body will cool down rapidly.
0:24:32 > 0:24:35This is really, really cold.
0:24:35 > 0:24:37I thought it would be swimming pool temperature.
0:24:39 > 0:24:4212 degrees is about the same temperature as the sea
0:24:42 > 0:24:45around the UK during the winter months.
0:24:45 > 0:24:4845 minutes in here? Are you having a laugh?
0:24:48 > 0:24:51The team are using a thermal imaging camera
0:24:51 > 0:24:53to show where her body is losing heat.
0:24:53 > 0:24:57White is hot, red is warm and blue is cold.
0:24:57 > 0:25:01This feels like icy water. It doesn't feel like cold water.
0:25:01 > 0:25:04Your deep body temperature is now 36.85.
0:25:04 > 0:25:09Our cut off in terms of as low as it can go is 35.
0:25:09 > 0:25:11How long left?
0:25:11 > 0:25:14Um... you've got about eight minutes.
0:25:14 > 0:25:16As well as body temperature,
0:25:16 > 0:25:19Mike is also keen to know how she's feeling.
0:25:22 > 0:25:24- Um... There.- There?
0:25:24 > 0:25:26OK, so now you're starting to get uncomfortable
0:25:26 > 0:25:29because of all the shivering that's going on.
0:25:29 > 0:25:32OK, that's it. Out we come!
0:25:32 > 0:25:33Well done!
0:25:33 > 0:25:37After 45 minutes the thermal imaging camera shows
0:25:37 > 0:25:39there's no heat coming from Helen's body
0:25:39 > 0:25:44and her core body temperature has dropped by 1.5 degrees.
0:25:44 > 0:25:48She's lost all control of her arms and the reality of how
0:25:48 > 0:25:52exposure to cold conditions can affect her body is hitting home.
0:25:52 > 0:25:54My arms feel...
0:25:54 > 0:25:56- That's right.- ..as if they're being gripped.
0:25:56 > 0:25:58This area is really easy to cool
0:25:58 > 0:26:00because it has such a high surface area,
0:26:00 > 0:26:04and a small mass so the arms are important to stay protected.
0:26:04 > 0:26:07We'll get you into the warm as quickly as we can.
0:26:10 > 0:26:12- Well done.- Oh, that's so good!
0:26:12 > 0:26:15Well, we'll get more in there for you cos you'll cool it down.
0:26:15 > 0:26:19When I first was lowered into that water, I did panic and it was...
0:26:21 > 0:26:23..really horrible and I thought,
0:26:23 > 0:26:25"There's no way I'm going to stay in here.
0:26:25 > 0:26:28"I'm not going to be able to warm up,
0:26:28 > 0:26:30"I'm not going to be able to get into a hot bath.
0:26:30 > 0:26:34"I'm going to be cold the whole time I'm there."
0:26:34 > 0:26:36And the clock is ticking.
0:26:36 > 0:26:39There's now only four months to go until Helen's polar challenge,
0:26:39 > 0:26:43when she'll have to be mentally and physically ready to cope
0:26:43 > 0:26:46with the freezing temperatures of Antarctica.
0:26:46 > 0:26:49It's a daunting prospect, but she's determined to succeed
0:26:49 > 0:26:50and raise awareness for Sport Relief
0:26:50 > 0:26:54so that children like Issa can get the help they need.
0:26:54 > 0:26:57And if you've been inspired by Helen's challenge,
0:26:57 > 0:26:59why don't you go the extra mile and get involved
0:26:59 > 0:27:01in Sport Relief this year?
0:27:01 > 0:27:04Get a grown-up and sign up to do the Sport Relief mile.
0:27:06 > 0:27:08There are hundreds of events
0:27:08 > 0:27:11and by raising money, you can help poor
0:27:11 > 0:27:14and vulnerable people in the UK and around the world.
0:27:16 > 0:27:20Next time, Helen's in California getting to grips with her
0:27:20 > 0:27:22specially built ice bike for the first time.
0:27:22 > 0:27:26I'm not sure it's that easy to peddle in all this gear!
0:27:26 > 0:27:28You can already see that she's exhausted.
0:27:28 > 0:27:32Sand stands in for snow in a back-breaking training session.
0:27:32 > 0:27:33Fun for five minutes.
0:27:33 > 0:27:37Practical for 500 miles? I don't think so.
0:27:37 > 0:27:40And a gruelling 15-mile off-road bike race
0:27:40 > 0:27:42puts her cycling skills to the test.
0:27:42 > 0:27:44I haven't fallen off yet!
0:27:53 > 0:27:56Subtitles by Red Bee Media Ltd
0:27:56 > 0:27:58E-mail subtitling@bbc.co.uk