In this episode of Wellness Big Sis the Pod, Dr. Kelsy Vick breaks down what we learned this year about the female body, metabolism, and exercise science.

We revisit the science of fasting for women and why intermittent fasting can impact women differently than men — especially when it comes to hormones, metabolism, and body composition. We also dive into the truth behind Zone 2 cardio, HIIT, and SIT training, debunking myths about cortisol and explaining why high-intensity work still deserves a place in women’s routines.

This episode also highlights the importance of jump training for women, why it matters for bone health and long-term resilience, and how just a few minutes per week can make a big difference. Finally, we revisit why strength training really is that girl — and why it’s essential for women’s health at every stage.

If you want a science-backed approach to fitness, hormones, and training smarter as a woman, this episode ties it all together.

76:: Strength Training https://wellness-big-sis-the-pod.captivate.fm/episode/copy-of-pod-76-strength-training-pod/

74:: Jump Training https://wellness-big-sis-the-pod.captivate.fm/episode/74-the-forgotten-essential-in-your-exercise-handbag-jump-training/

73:: HIIT & SIT https://wellness-big-sis-the-pod.captivate.fm/episode/73-the-controversial-hiit-sit-conversation-why-both-are-essential-parts-of-our-exercise-routines-as-women/

63:: Fasting as women https://wellness-big-sis-the-pod.captivate.fm/episode/63-the-truth-and-science-behind-fasting-as-women/

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00:00- 00:17 Intro

00:18- 00:31 Introduction and Year in Review

00:31- 01:03 The Science of Fasting for Women

01:04- 04:37 Understanding Metabolism in Women

04:38- 11:15 High Intensity Interval Training (HIIT) for Women

11:16- 16:22 The Importance of Jump Training

16:23- 19:35 Strength Training: The Popular Girl

19:36- 20:37 Conclusion and Final Thoughts

2025 has been quite the year for the podcast.

2

So let's take a look back at 2025 and

some of the really fascinating things

3

we've learned about the female body.

4

Welcome back to Wellness Big Sis the Pod.

5

I'm your host, Dr.

6

Kelsy Vick, a board certified

orthopedic doctor, physical therapy,

7

and a pelvic floor physical therapist.

8

This first clip is from podcast

episode 63, where we covered

9

the science of fasting as women.

10

We talked to two experts

earlier in the year, Dr.

11

Katie Hirsh and Mel Silver, and they

both mentioned fasting affecting women.

12

Differently than men

13

And why we as women might not want to

choose fasting if our goal is truly

14

on body composition changes due to the

different signaling within our bodies.

15

Speaker: So let's switch

to metabolism a little bit.

16

And this is where women actually

thrive because we are metabolically

17

superior or metabolically more efficient

or more flexible in how we utilize

18

certain fuel sources within our body.

19

We are able to switch between

different fuel sources and take

20

from different fuel sources more

efficiently than a man system is.

21

So historically, I guess what we

utilize for our fuel sources has

22

typically followed this pathway.

23

We first utilize blood glucose, then

we utilize stored glycogen within

24

our liver and our muscles, which is.

25

The stored form of glucose.

26

So glycogen, glucose, you can

think of them as the same thing.

27

Glycogen to just takes a little bit

to get to the point where we can

28

use it as energy, as glucose, and

it is the stored form of glucose

29

in the liver and the muscles.

30

So we first tap into the blood

glucose levels, 'cause that's

31

usually the most available in the

most readily available for us.

32

Then we tap into liver and

muscle glycogen stores and then

33

we tap into free fatty acids.

34

That's historically what we've believed.

35

As how a body taps into different fuel

sources for energy, whether that's for

36

exercise or just like day-to-day tasks.

37

However, it's been shown that women

specifically have this flexibility

38

within their metabolic system where

we tap into that blood glucose first.

39

But then we actually transition

to those free fatty acids a

40

lot quicker than a man does.

41

They have to go through that process

where we can go straight from blood

42

glucose utilizing blood glucose

as our fuel to free fatty acids.

43

And this is because we have a

lot more oxidative fibers within

44

our skeletal muscle tissues.

45

And so that is one of the theories

that has been brought up to why

46

we tap into those free fatty

acids quicker than Amand does.

47

So one of the goals with fasting could

be, Hey, let's decrease our glucose

48

stores initially so that we tap into

those free fatty acid quicker, or, that's

49

historically been one of the theories.

50

And for a man that might actually make

sense because if we can limit the amount

51

of glucose that they have to utilize

at the beginning of that pathway,

52

they might tap into those free fatty.

53

Storage is early on in their workout.

54

Where for women, we don't

actually have to do that.

55

We kind of skip that step.

56

We skip the benefit of fasting

because we utilize that glucose

57

within the bloodstream first before

we tap into those free fatty acids.

58

And a lot of people think, oh, let's

tap into those free fatty acids as fuel.

59

As soon as we can so

that we're burning fat.

60

But this is not necessarily

like a one-to-one ratio.

61

Yes, it does help that we can tap

into those free fatty acids, but

62

it's a lot more complex than that.

63

But that is one of the reasons fasting

has been promoted is because if we

64

can decrease the circulating glucose

levels or stored glucose levels, then

65

we might be able to tap into those

free fatty acids sooner, whereas women.

66

We have that flexibility to go, okay,

utilize all that blood glucose first.

67

That's circulating quick energy first

before we tap into those free fatty acids.

68

But we don't necessarily have to

go through the entire process that

69

we've historically thought that a.

70

Men go through, but maybe a woman

does not necessarily go through.

71

Speaker 7: The rest of the episode

covers Why fasting affects our

72

hormonal systems, but also the

research on when fasting might be

73

appropriate for some women and that.

74

Subsect of women is in the minority.

75

So take a look at episode 63, especially

if you are interested in learning

76

about fasting for the female body.

77

Another hot topic is the topic of

high intensity interval training and

78

sprint interval training for women.

79

And I think the reason they're

so controversial is because of

80

this big push in lowering and

decreasing our cortisol levels.

81

So in podcast episode 73, we chat

Why high intensity interval training

82

and sprint interval training are

especially important for us as women?

83

And why zone two shouldn't necessarily

be getting all of the hype when

84

it comes to our training as women?

85

Speaker 4: So the first foundation

we'll talk about is definitely one

86

of the most controversial, which is

why I wanted to start out with it.

87

but we'll talk about high

intensity interval training

88

and sprint interval training.

89

So hit involves short bursts of activity,

typically 45 seconds to a few minutes

90

at 85 to 90% of your heart rate max, or

85 to 90% effort, followed by usually

91

a one-to-one work to recovery ratio.

92

So if you like, if you do the exercise

for a minute, you're also recovering

93

for a minute, but that can vary.

94

But that's just a general rule of thumb.

95

So for sprint interval training,

it's a shorter duration at a

96

hundred percent max effort.

97

But basically max effort for 20 to 30

seconds, followed by a longer recovery,

98

like two to four minutes in between.

99

So why do high intensity interval

training and sprint interval

100

training get a bad reputation?

101

I think it comes down to cortisol.

102

There's been a big push around.

103

Cortisol, I guess, propaganda.

104

Cortisol is truly that

misunderstood, mean, girl.

105

We need it within our bodies,

especially to build muscle.

106

We also need it in order to

have energy throughout the day.

107

We need it to exercise.

108

We want it to elevate during exercise,

which I think is why hit and sit.

109

Have this sort of negative connotation.

110

However, with high intensity interval

training and sprint interval training,

111

what we expect and what we want with

our bodies is a momentary spike in

112

cortisol, a momentary cortisol elevation.

113

During that exercise followed by

our bodies being able to return

114

to baseline, we do not want

sustained cortisol elevation, but.

115

If we do the appropriate things

surrounding high intensity interval

116

training and surrounding sprint interval

training, including a proper cool

117

down, proper breath work, we should

be able to help control that cortisol

118

elevation that naturally happens,

and we want to happen with exercise.

119

Over time, high intensity interval

training and sprint interval training

120

have also actually been shown to

lower that baseline level of cortisol.

121

So not within one session.

122

We expect a spike within each

exercise session, but over time,

123

the more we incorporate HIIT and

sit into our routines, the better

124

our body adapts and it's actually

beneficial to our cortisol long term.

125

So why are high intensity interval

training and sprint interval training

126

so important to have as part of our

essentials and our exercise handbags,

127

especially as women, a lot of it

comes down to our skeletal muscle

128

and our mitochondrial density.

129

As women, we naturally have more type one

skeletal muscle tissue fibers compared

130

to men, and these type one fibers are.

131

Built more for low load

long duration work.

132

So think long runs your type one

skeletal muscle fibers are the ones

133

that help with your postural muscles

and standing up without falling

134

over With our posture, you're having

to hold a position, low load, low

135

weight for a long period of time.

136

So these are where those type one

skeletal muscle fibers come into play.

137

Men on the other hand have more

type two A and type two X fibers,

138

which are known for these fast

explosive power-based movements.

139

So think sprinting, jumping, those

like really quick bouts of effort,

140

those are what those type two skeletal

muscle fibers are utilized for.

141

And the ones that men have

proportionally more of compared to women.

142

So as we all age, men and women,

our skeletal muscle fibers start

143

to shift to have more type one

muscle fibers compared to type two.

144

And it's really important that as we

age, we try and maintain those type

145

two skeletal muscle fibers because

they help us with catching ourselves.

146

If we're about to fall standing up out

of a chair, which you don't necessarily

147

think of those as power-based activities

now, but we need that quick reaction time

148

in order to help ourselves if we start

to trip over a rug or in order to get

149

out of a chair, especially as we age.

150

So as women, we also have a higher

mitochondrial density than men, meaning

151

we are naturally shifted to be able to

handle more endurance based exercises

152

better than men because we naturally have

more type one skeletal muscle fibers, and

153

we have a higher mitochondrial density.

154

We need to work.

155

What we're not as good

at, if that makes sense.

156

So structurally and physiologically,

we have a predisposition towards more

157

of those endurance based activities.

158

So we really need to work on the opposite,

so that high intensity, that sprint

159

intensity training in order to help

maintain and increase some of those type.

160

Two fibers, and then also maintain

those fibers as we age in addition

161

to working more of that anaerobic

system within our bodies that

162

doesn't necessarily need oxygen in

order to power certain movements.

163

Since we do have such a high capacity

for using oxygen for our movements

164

with that increased mitochondrial

density, I know that's a ton of science.

165

But basically we are shifted more

towards those endurance based exercises.

166

We're gonna be better at those

in general across the board

167

compared to our male counterparts.

168

So since we are shifted that way, we

wanna be able to train the opposite,

169

not only for the health of our

bodies currently, but also long term.

170

So it boils down to if we

don't use it, we lose it.

171

And when we don't have it as

much as a guy does, we definitely

172

wanna train that system even more.

173

Speaker 7: If cortisol elevation is

something that you're concerned about.

174

We also chat through some ways to

incorporate high intensity interval

175

training and sprint interval training,

while also performing different

176

actions and behaviors to help manage

those cortisol levels, especially

177

after that high intensity interval

training or sprint interval training.

178

one of the biggest segments of

learning about the female body

179

in the year 2025 on wellness.

180

The pod came from our exercise

handbag series that we did

181

in the fall where we covered.

182

Why our bodies need certain forms of

exercise and how to incorporate those no

183

matter the style of exercise handbag that

you like, whether you like traditional

184

lifting, Pilates, bar, swimming,

running, whatever sort of exercise you

185

enjoy, there are ways to incorporate

these essentials or these handbag

186

necessities into our exercise routines

and our exercise handbags is women.

187

One of our most forgotten essentials

in our exercise routines and

188

exercise handbags is women.

189

Is jump training and in episode 74 we

chat why we shouldn't forget it and

190

why it is so important for us as women.

191

Speaker 5: You might be

thinking jump training Kelsey.

192

What even is jump training?

193

It's as simple as it sounds really.

194

It's jumping, it's loading your body,

your musculoskeletal system with

195

extra than your body weight with more

ballistic movements that increase the

196

amount of load that you're placing

on your musculoskeletal structure,

197

your joints, your muscles, your

bones, your ligaments, your tendons.

198

All of it.

199

It is all affected in a beneficial way

with jump training and is especially

200

important for us to include as women.

201

So a little backstory that we've

mentioned on the podcast before, but

202

if it's your first time joining us, I

wanna make sure that we have a little

203

bit of a physiology lesson for when

we start to talk about some of the

204

benefits of jump training on our system.

205

So as we age, no matter if you're male

or female, we start to lose bone mineral

206

density as we age, where bone breakdown.

207

Outpaces bone formation, and this

is especially the case with women.

208

Women are at a higher risk for developing

osteopenia, which is basically weaker

209

bones and the prerequisite or the one

that comes before osteoporosis, which

210

is a lot of time, what you hear about in

older individuals and what increases the

211

likelihood of fractures within the bone.

212

So osteoporosis is the more

advanced stage of that.

213

Bone breakdown, that starts

to be extra concerning.

214

And as women, we have a higher

risk of developing both.

215

So it's this imbalance, let's say

that we're constantly fighting against

216

as we age, oftentimes after the age

of about 30, it happens pretty young

217

where we start to see some of the

slowdown of that bone formation.

218

This process affects women more than men.

219

So it's super duper important for us as

women to load those bones and provide

220

sufficient stimulus to our bones so that

we can build bone in our younger years,

221

our adolescent and young adult years.

222

And then also work against the

natural physiologic process

223

of bone breakdown as we age.

224

And there are studies that show

through purposeful stimulus, whether

225

that is jump training or another

essential in our handbag that we'll

226

talk about later in the month.

227

We can actually work to combat

some of that bone breakdown.

228

In our younger years, a lot of

people don't know about and don't

229

know how to positively build that

foundation of bone marrow densities.

230

So it is something to watch out for

no matter if you're male or female,

231

but especially if you are a female

because the max amount of bone

232

mineral density, the foundation for

our bones, the strength of our bones.

233

Is developed in those

adolescent teen 20 years.

234

So it's super duper important that we

build that foundation in our younger

235

years so that when we're older and

our bone breakdown is naturally

236

outpacing our bone formation, we have

this greater foundation to stand on.

237

So how can we actually strengthen our

bones to build that solid foundation

238

in our teens, twenties, thirties?

239

This is the time where we

can optimize that foundation.

240

And really honestly, in our

adolescence, up to 40% of our bone

241

marrow density is formed by puberty.

242

So there's a sharp increase in our younger

years, and then it starts to plateau off.

243

To where in our later years we're

fighting against this decline, and we

244

really wanna make sure that we build

up the strength of our bones early

245

on so that we can reduce the slope

of that decline and maintain some of

246

that bone marrow density as we age.

247

So how do we strengthen our bones?

248

Bones respond to mechanical load

in multiple directions, similar to

249

how you think about muscles, right?

250

When we stress a muscle, it starts

to send reinforcements in order to

251

build up that muscle, to be able to

tolerate that load the next time.

252

Muscles pull on bones.

253

So the same thing happens to our bones.

254

Bones start to respond to that

mechanical load, that stress and strain

255

in a lot of different directions.

256

So in a similar way that our

body is queued to build muscle

257

in areas during training.

258

Our bones are also queued to build

more bones in area that we load.

259

And that load can come through

strength training or through

260

something like jump training.

261

And jump training is almost

like bone building on steroids a

262

little bit, especially as we age.

263

As a side note, muscles pull on

bones, so anytime we load the muscles,

264

we are also loading the bones.

265

The important thing for both

loading the muscles and the bones

266

is that we do it in a safe way.

267

Jump training sounds super

scary, especially for people who

268

aren't used to doing jump rope

and squat jumps or box jumps.

269

It can be super scary and it can.

270

Introduce us to injury if our bodies

aren't prepped and primed for it.

271

So a lot of the studies that say

how beneficial jump training is

272

actually start with the Foundational

Strength Training program to help

273

the body build that foundation for

when the researchers decided to add

274

that jump training into the program.

275

Speaker 7: In this episode, we also

chat how to incorporate it into your

276

routines, but it's one of the simplest

and quickest things to add to your routine

277

to get a lot of bang for your buck.

278

We cover the exact parameters in the

episode, but just know it shouldn't

279

take more than five-ish minutes

each week, oftentimes even less.

280

Lastly, one of the most beneficial things

for the female body strength training

281

we covered the Popular Girl strength

training in episode 76 as one of the final

282

episodes in our exercise handbag series.

283

Speaker 6: So as popular as strength

training is, it is for a very good reason.

284

It's very protective against

a lot of different things.

285

So not only does it help us with

our toning and our current aesthetic

286

goals, but it also is protective

for our entire musculoskeletal

287

system, our bone health, our brain,

our balance, especially as we age.

288

So strength training

affects us positively Now.

289

Way in the future, which is why it

really is the well-deserved popular

290

girl that everyone's talking about.

291

From the most basic standpoint, strength

training or resistance training is

292

muscle contraction against an external

resistance to improve strength,

293

endurance, or the size of a muscle.

294

So the important thing to note is that

we are contracting against a resistance,

295

whether that is shortening a muscle or

lengthening a muscle, or we can also have

296

static contractions against a resistance,

such as like holding a platter.

297

In your hand when you're at a

dinner party trying to serve food.

298

That's an example of a

static muscle contraction.

299

But you can do the same thing with a

dumbbell or with a weight or with a band

300

or a, a variety of external resistances.

301

So how does strength training

actually affect us physiologically?

302

The very first mechanism that we

gain strength by is actually through

303

neural adaptations, which is basically

improving the connection of our

304

brain to our skeletal muscle fibers.

305

Initially, strength training

increases our ability to recruit

306

those motor units, which is basically

a collection of muscle fibers that

307

are stimulated by a motor neuron.

308

Our bodies figure out

what to recruit better.

309

When we start a strength training program,

nerves are how we communicate with those

310

muscle fibers, and so this first little

strength gain that you might experience is

311

actually based on our neural adaptations,

which basically means better communication

312

between our brain and our muscles.

313

Not necessarily increasing the size

of the muscles, but how we communicate

314

from our brain to our muscle tissue.

315

So physiologically, we also

experience muscle hypertrophy.

316

So when we lift a super heavy resistance,

our muscles undergo small micro tears or

317

micro damage that basically stimulates

a rebuilding and repair process.

318

That is why rest and

recovery is so important.

319

Exercise is actually the stimulus.

320

For muscle growth, but it's not

where muscle growth happens.

321

It just stimulates that micro damage

to cue our bodies, to send in all

322

of those resources to repair and

rebuild stronger than we were before.

323

So muscle is repaired and rebuilt

during the recovery exercise is

324

just the stimulus for that repair.

325

Our body is queued to reinforce that

area so that we can handle the load

326

better next time, which is why it's

also important that we consistently load

327

the muscles bit by bit over time in a

heavier way so that we don't become static

328

and plateau at a certain resistance.

329

We always want to be pushing that

threshold a little bit more to

330

stimulate that muscle hypertrophy.

331

Speaker 7: Of course, we chatted

through the benefits of strength

332

training and overall why strength

training really is that girl, but

333

also how to incorporate it into your

routine even if you don't typically

334

like strength training or lifting.

335

We covered so much of the

female body this year.

336

Of course, it's one of my favorite

subjects as a physical therapist and

337

one that I'm constantly researching,

constantly learning about, and constantly

338

trying to make that education and that

research easier for other people to

339

understand because there's so much

conflicting evidence out there, especially

340

when it comes to what we need as women.

341

And my whole goal is to really try to.

342

Give people, especially girls, this

education a lot earlier in life so that

343

we can set ourselves up for success

later on, especially when we're in

344

our eighties, nineties, and we might

struggle with fall risk or decreased

345

bone mineral density, things that might

make our mobility our function, our

346

everyday lives a little more challenging.

347

So I love talking about the female body

and it was hard to narrow down some of

348

my top moments from talking about the

349

probably some of my four favorites and

some of the four topics that I really want

350

people to come back to and understand.

351

So I hope you enjoyed this episode and

I'll see you guys again on the next

352

episode of Wellness Big Sis the Pod.