Jimmy Sosinski - 2026 IRONMAN 70.3 Northern California
QT2 Systems โ€ข 2026 IRONMAN 70.3 Northern California

Jimmy Sosinski

This race is not a test of whether you can handle the heat. It is an opportunity to better understand what good racing looks and feels like when the conditions are suppressing the numbers.

Bike Critical Power
315 W
Run Critical Speed
5:31/mi
Race Purpose
Race + Learn

Race Strategy at a Glance

You already train in heat and humidity that provide a substantial heat-acclimation stimulus. You have raced well in warm conditions before. You know how to fuel, hydrate, pace, and manage yourself.

This is a B/C race during the middle of your Kona build. You are in very good 70.3 shape, particularly from a durability standpoint, but you are not trying to manufacture peak fitness for this race. We reduced enough training to shed recent fatigue and give you access to the fitness you currently have.

There are two legitimate goals:

  • Race well.
  • Learn something useful for Kona.

You are an experienced, intelligent racer. There is very little here that requires you to be managed minute by minute.

The primary challenge is interpretation.

If the conditions turn a wattage you believe should be 275 W into 265 W, or a pace you believe should be 6:05/mi into 6:18/mi, do not automatically interpret the difference as poor performance.

In hot conditions, we are lesser. Everybody is.

Good heat racing is not reproducing cool-condition numbers. Good heat racing is producing the best sustainable output the conditions allow.

Race the conditions you are inโ€”not the conditions you wish you had.

Your Primary Race Anchors

Swim CS ~1:30/100 yd
Expected Swim ~30โ€“33 min
Wetsuit Race-day decision
Swim Context Strong swimmer
Bike CP 315 W
Bike LT1 ~249 W
Bike OGC ~280 W
Bike THR ~168 bpm
Flat 70.3 Power ~268โ€“280 W
Chattanooga Bike HR ~144 bpm avg
Run CS ~5:31/mi
Run THR ~179 bpm
Run LT1 ~6:29/mi
Run OGC ~5:48/mi
Ideal 70.3 Pace ~5:56โ€“6:08/mi
Chattanooga Run ~6:25/mi @ 156 bpm

These numbers provide context. They do not dictate what the heat must allow you to produce.

Your Control System

You do not need a rigid hierarchy telling you which metric to follow. You understand your body well enough to integrate all of them.

Bike Power Tells you what you are producing.
Heart Rate Tells you what that production is costing.
RPE Tells you whether that cost makes sense.

On the run, pace describes the result. Heart rate and RPE tell you whether that pace remains sustainable.

Heat complicates the relationship between all three. That is the point of this race.

The Most Important Heat Concept

Heat does not suddenly become a problem at mile 45 of the bike or mile 8 of the run. It accumulates.

You can feel completely fine while thermal load is already increasing beneath the surface.

As body temperature rises, cardiovascular demand rises. That means the same power or pace may require progressively higher heart rate and perceived exertion.

That is not automatically a problem.

It becomes a problem when you continue demanding the original output after the physiological cost has materially changed.

The target does not change because it is hot. The target changes when the cost of producing it changes.

You Are Already Heat Acclimated

This race is not the beginning of your Kona heat preparation.

Your normal Mid-Atlantic training environment already gives you repeated exposure to high temperatures and significant humidity. In many of those conditions, evaporative cooling is impaired substantially.

Northern California is likely to be much drier. That does not make the heat harmless, particularly with very high air temperatures and direct sun, but it does mean the environment is different from the humid heat you routinely train in.

You are not waiting to become someone who can race in the heat. You already are someone who races in the heat.

The goal is to learn to trust that.

What Good Heat Racing Looks Like

Being good in the heat does not mean the heat does not affect you.

  • You recognize the effect earlier.
  • You adjust appropriately.
  • You maintain hydration and cooling.
  • You do not panic when the numbers change.
  • You preserve more performance than athletes who manage the conditions poorly.
  • You continue producing late in the race.

Your competitors are being affected, too. Some of them will simply fail to recognize it until later.

That can become an advantage for you.

Heat Decision Framework

GREEN โ€” Everything Still Matches Your output, HR, and RPE make sense together. You may be hot. HR may be slightly elevated. The race may feel harder than it would in cooler conditions.

Nothing appears disproportionately expensive.

Action: race normally.
YELLOW โ€” Heat Accumulation Is Becoming Visible HR is drifting upward at the same approximate output. RPE may be slightly higher. The numbers no longer look quite as pretty as they did earlier, but the effort is still controlled.

Action: do not panic. Stay ahead of hydration. Increase cooling. Favor the lower portion of the appropriate output range.
RED โ€” The Cost Has Changed The same power or pace now requires substantially more HR and RPE. Breathing, mechanics, or the ability to sustain the output are clearly deteriorating.

Action: reduce external workload and stabilize the physiology so you can continue racing.

Do not waste mental energy being irritated that the numbers have changed.

Mental Execution

When you are racing exceptionally well, you tend to be a happy athlete.

You smile. You talk. You engage with the people around you.

You look like someone who is having fun racing.

That is worth paying attention to.

If you find yourself becoming inwardly irritated because the Garmin is showing a number below what you believe you should be capable of producing, recognize that for what it is:

Unnecessary mental energy.

The number may simply be telling you that it is hot.

It does not require judgment.

It requires interpretation.

A heat-adjusted number is not an underperformance.

Get back to racing.

Swim Execution

The swim should be one of the least complicated parts of your day.

You are a strong swimmer. You are comfortable in open water, comfortable with contact, good at navigating, and good at using feet.

Wetsuit status may remain uncertain until close to race morning. That affects speed, but it does not materially change the strategy.

If it is wetsuit legal, take the free speed.

If it is not, swim exactly the way you know how to swim.

1. Establish
Start โ†’ Approx. 200โ€“300 m
Objective
Get position
Priority
Useful feet
Cost
Don't overspend

Get position without spending unnecessarily.

You do not need to prove anything in the first few hundred meters.

Find useful feet and settle into the race.

Cue: Get established.
2. Settle Into the Group
Approx. 300โ€“1,200 m
Position
Stay on useful feet
Sighting
Minimum necessary
Priority
Make it inexpensive

Once you are positioned well, make the swim inexpensive.

  • Stay tight to useful feet.
  • Sight only as much as necessary.
  • Let the group do some of the work.
  • Do not turn small positioning changes into unnecessary surges.
Cue: Make the swim cheap.
3. Finish Ready to Race
Final Approx. 500โ€“600 m
Position
Maintain
Stroke
Stay smooth
Priority
Prepare to ride

Maintain position. Stay smooth.

Begin preparing to transition from swimmer to bike racer.

No reason to manufacture a heroic final several hundred meters.

Cue: Finish ready to ride.

T1

Efficient.

Calm.

Get onto the bike and begin the part of the race where your competitive strength really starts to matter.

Bike Execution

Your bike-run combination is one of your biggest weapons.

You do not need to create that advantage by forcing the bike.

You create it by riding appropriately enough that you can still express your run later.

The course rewards intelligent variable power.

The objective is not a beautiful average-power number.

It is the fastest bike split the terrain and conditions allow at a cost that preserves your ability to run.

Uphill: spend appropriately.
Crest: release.
Downhill: collect.

How to Ride the Rollers

Your idealized flat/steady 70.3 range is approximately 268โ€“280 W.

That is not a requirement to produce the same number everywhere.

Flat / Steady
268โ€“280 W
Primary race pressure
Long Gradual Rise
282โ€“295 W
Use where road rewards it
Moderate Roller
295โ€“310 W
Shorter rises / momentum
Steeper Ramp
310โ€“325 W
Selective + brief
Upper Ceiling
325โ€“340 W
Occasional / very short

The higher power rises above your normal race range, the shorter the exposure should become.

The Other Riders Are Irrelevant

You are likely to encounter athletes riding the rollers poorly.

  • Some will attack every rise.
  • Some will surge past you uphill and stop pedaling over the top.
  • Some will repeatedly turn a 70.3 into a series of 60-second bike races.

Let them.

Their decisions do not change yours.

You know how to ride terrain.

You do not need to win the rollers. You need to win the race you are actually racing.

Bike Heart Rate

Chattanooga gives us an important real-world data point:

You averaged approximately 144 bpm on the bike while putting together a very good race in warm conditions.

That is more useful than trying to force a generic percentage-of-threshold target onto you.

We should therefore use HR primarily as a cost monitor, not something you need to chase upward.

Early in the ride, establish what normal race power is costing on this particular day.

Then watch what happens to that relationship.

If approximately 270โ€“275 W initially produces one HR and later requires substantially more HR, the heat is becoming visible.

That does not automatically mean reduce power.

It means pay attention.

If the higher HR is accompanied by normal RPE, continue cooling and racing. If higher HR is accompanied by increasingly high RPE, the cost is changing. That is when output should change.

Bike Course Elevation Profile
56 miles
IRONMAN 70.3 Northern California bike elevation profile
Official IRONMAN course elevation profile.
1. Settle
Approx. Miles 0โ€“7
Steady Power
Build โ†’ 268โ€“280 W
Gradual Rollers
282โ€“295 W
HR
Establish baseline

You do not need the first five minutes of the bike to tell you anything profound.

  • Settle.
  • Get aero.
  • Start drinking.
  • Begin cooling.
  • Allow the bike to come to you.
  • If the computer is showing a number slightly below what you expected, do not immediately assign meaning to it.
Cue: Establish the bike.
2. Control the Rollers
Approx. Miles 7โ€“15
Steady
268โ€“280 W
Gradual / Moderate
282โ€“310 W
Steep / Brief
310โ€“325 W

325โ€“340 W is available only very briefly and selectively.

  • Ride your own race.
  • Do not become mentally involved with athletes repeatedly surging the terrain.
  • Release pressure as the grade eases.
  • Do not continue climbing watts across the crest simply because another athlete does.
Cue: Let them race the hills. You race the course.
3. Work
Approx. Miles 15โ€“23
Steady
268โ€“280 W
Most Rollers
282โ€“310 W
Control
Power + HR + RPE

This is where the race begins to settle into a meaningful working rhythm.

If power looks appropriate, HR is behaving reasonably, and RPE is controlled, continue racing normally.

Do not force output because you think a certain number should be there.

Equally, do not unnecessarily reduce output just because it is warm.

Heat check: Is the wattage lower because the heat has changed the sustainable costโ€”or am I simply annoyed that the computer isn't showing what I expected?

Cue: Interpret. Don't judge.
4. Release
Approx. Miles 23โ€“31
Power
Let terrain dictate downward
Priority
Aero + momentum
Mindset
Don't protect average power

As the terrain becomes more favorable, stop caring about producing your flatland power range.

If you are moving quickly at 250 W, that's excellent.

If you are moving very quickly at 230 W, that may be even better.

Watts only matter when they buy speed efficiently.

  • Stay aero.
  • Carry momentum.
  • Continue drinking.
  • Continue cooling.
Cue: Watts have to buy something.
5. Collect
Approx. Miles 31โ€“43
Priority
Cheap speed
Hydration
Stay completely current
Heat
Watch accumulation

This portion of the course gives you an opportunity to accumulate speed without accumulating unnecessary physiological cost.

Take it.

  • Stay aero.
  • Pedal where it matters.
  • Let gravity work where it does not.
  • Keep drinking before thirst becomes urgent.
  • Keep cooling before you feel overheated.

You may still feel good while cardiovascular strain is slowly increasing.

The goal remains to urinate at least once on the bike, with one to two times being appropriate.

Cue: Cheap speed. Stay ahead of the heat.
6. Reassess
Approx. Miles 43โ€“49
Question 1
What power?
Question 2
What HR / RPE cost?
Question 3
How is hydration?

The road begins demanding more again.

Do not compare your speed with the faster terrain you just left.

Instead, reassess:

  • What power am I producing?
  • What HR does it require now?
  • What does that power feel like?
  • Am I still controlling the heat?
  • Am I current with fluid?

If normal race wattage still feels normal: race normally.

If the same wattage is clearly becoming more expensive: allow the wattage to come down.

A lower number because of heat is not weakness.

It is correct execution.

Cue: Race the cost, not the expectation.
7. Finish the Bike Without Protecting the Bike Split
Approx. Miles 49โ€“56
If Physiology Is Good
Continue normally
If Heat Is Accumulating
Trim output
Priority
Bring the run to T2

You have an excellent run.

Bring it with you.

If the physiology remains good, continue riding normally.

If heat accumulation is becoming obvious, this is not the time to protect average power.

  • Trim the output.
  • Reduce unnecessary roller spikes.
  • Stay hydrated.
  • Continue cooling.
  • Do not spend run fitness to rescue a number on the bike computer.
Cue: Bring the weapon to T2.

T2

The bike is finished.

Whatever number it produced is now irrelevant.

Do not evaluate it.

Start running.

Run Execution

Your run off the bike is not merely good.

It is a weapon relative to the athletes you race against.

Chattanooga is useful evidence.

You ran approximately 6:25/mi at an average HR around 156 bpm on a warm, rolling course.

The important lesson is not that 6:25 is your run capability.

It clearly is not.

The lesson is that a heat- and terrain-adjusted pace can still represent excellent racing.

Your ideal-condition 70.3 capability is closer to approximately 5:56โ€“6:08/mi.

California may not allow that.

That is okay.

The race is about producing the fastest sustainable pace available at the correct physiological cost.

Run Heart Rate

Chattanooga gives us another useful anchor:

Approximately 156 bpm average while running very well in warm conditions.

That does not mean 156 is the target here.

It tells us that you do not need a very high HR to race a strong 70.3 run.

Use HR as context.

If the pace is slightly slower than expected but HR and RPE are appropriate, you may be racing extremely well.

Do not demand a faster pace simply because your cool-condition model says you should be capable of it.

Run Course Elevation Profile
13.1 miles
IRONMAN 70.3 Northern California run elevation profile
Official IRONMAN course elevation profile.
1. Restrain
Approx. Miles 0โ€“2
Opening Pace
~6:10โ€“6:20/mi
Conditions
Allowed to dictate
Priority
Settle + cool

This is not because you are incapable of running faster.

It is because the correct opening pace in significant heat should feel almost suspiciously manageable.

  • Let your mechanics settle.
  • Immediately begin cooling.
  • Do not wait until you feel hot.
  • If pace looks slower than expected, ask what HR and RPE say before deciding that something is wrong.
Cue: Establish the runโ€”not the final pace.
2. Establish
Approx. Miles 2โ€“6
Possible Pace
~6:05โ€“6:20/mi
Primary Control
HR + RPE
Priority
Sustainable rhythm

If conditions and physiology are good, begin moving toward the fastest sustainable rhythm available.

That may be near 6:05.

It may be 6:15.

It may be 6:20.

The watch does not get to decide this.

What Matters

  • Is HR behaving?
  • Is RPE controlled?
  • Are mechanics good?
  • Are you cooling?
  • Are you continuing to fuel and hydrate normally?

If yes, continue.

Cue: Good heat racing may look slower.
3. Assess
Approx. Miles 6โ€“10
If Controlled
Increase pressure
If Pace Is Slower
Don't judge it
If HR + RPE Rise
Stabilize

This is where the race becomes especially valuable for Kona.

You now have enough accumulated thermal stress to learn something.

If pace remains strong and HR/RPE remain appropriate, increase pressure.

If pace has slowed modestly but you remain in control, do not judge it.

If HR and RPE are both climbing aggressively, allow pace to soften enough to stabilize.

The athlete running 6:20 intelligently may be racing much better than the athlete forcing 6:05 and preparing to run 7:30 later.

This is where your durability and experience begin to matter relative to the field.

Cue: Stay in the race you're actually having.
4. Race
Approx. Miles 10โ€“13.1
Primary Goal
Use what remains
HR
Allowed to rise
Priority
Race

Now the learning portion of the experiment gives way to racing.

If you have managed the conditions well and you still have more: use it.

You do not need to protect yourself for Kona here.

You simply did not need to waste yourself early in order to prove anything.

If HR rises late because you are racing harder, that is appropriate.

If pace remains slower than cool-condition expectations because the day is hot, that remains irrelevant.

  • Mile 10โ€“11: increase pressure.
  • Mile 11โ€“12: race.
  • Mile 12โ€“13.1: use what remains.
Cue: Now race.

Cooling and Hydration

Do what you already know how to do.

This is not the race to reinvent your fueling system.

Fuel normally.

Hydrate normally, with the understanding that heat increases fluid loss and therefore increases the importance of staying ahead of hydration.

Bike Hydration Check

Aim to urinate at least once, with one to two times being entirely appropriate.

Do not force fluid simply to achieve that metric.

Use it as one additional piece of information.

Cooling

Take advantage of cool water whenever practical.

In dry conditions, evaporative cooling can be especially useful.

If sweat is accumulating on the skin instead of evaporating, wipe away the warm moisture and replace it with cool water.

Do not allow warm fluid to sit on the surface when you can replace it with cooler water.

Race-Day Decision Rules

The computer shows lower bike power than expected Ask: What does it cost? If HR and RPE are appropriate, continue racing. If HR and RPE are elevated, allow power to come down. Do not get irritated with the number.
Other athletes attack the rollers Let them. Their pacing decisions are not your problem.
Pace is 10โ€“15 sec/mi slower than expected Check HR. Check RPE. Check mechanics. Check heat. If all of those make sense, continue. Heat may simply have changed what good racing looks like.
HR is drifting upward HR drift alone is information. Do not automatically slow down. If RPE remains controlled, continue cooling and monitor.
HR and RPE are both escalating Now act. Reduce external workload. Cool aggressively. Get the system back under control.
You feel good late Race!

Your Competitive Advantage

A lot of athletes can generate impressive numbers when conditions are favorable.

The athlete who can continue racing when conditions are unfavorable is much harder to beat.

  • Your routine training provides significant exposure to difficult heat and humidity.
  • You have a strong swim.
  • You ride intelligently.
  • Your bike-run combination is a weapon.
  • You are durable.
  • You make very good race-day decisions.

The opportunity here is not to prove that heat does not affect you.

It does.

The opportunity is to see that you may handle the effect better than the people around you.

The Kona Lesson

You are already doing the heat acclimation for Kona.

This race is an opportunity to trust that.

Kona will bring its own challengesโ€”especially direct solar loadโ€”but you are not going there as an athlete who has spent the summer training in cool conditions and hoping to suddenly adapt.

You routinely train in difficult heat and humidity.

That matters.

What we want you to take away from this race is a better understanding of:

  • What appropriate heat-adjusted power looks like.
  • What appropriate heat-adjusted pace looks like.
  • How HR drifts as thermal load accumulates.
  • When that drift is harmless.
  • When rising HR and RPE actually require an adjustment.
  • How much performance you can continue producing late in the race when you manage the heat correctly.

Being good in the heat does not mean the heat doesn't slow you down. It means you understand the slowdown, manage it, and keep racing while other athletes begin paying for their mistakes.

Quick-Reference Race Card

Section Primary Target HR / Heat Check Execution Cue
Swim โ€” Establish Start โ†’ ~300 m Find useful feet Controlled opening Get positioned without overspending. Get established.
Swim โ€” Settle ~300โ€“1,200 m Draft + navigate Stay economical Make the swim inexpensive. Make the swim cheap.
Swim โ€” Finish Final ~500โ€“600 m Maintain position Stay smooth Exit ready to race. Finish ready to ride.
Bike โ€” Settle 0โ€“7 mi Steady: build โ†’ 268โ€“280 W
Gradual: 282โ€“295 W
Establish today's power / HR / RPE relationship. Aero. Drink. Cool. Don't assign meaning to an early low number. Establish the bike.
Bike โ€” Rollers 7โ€“15 mi Steady 268โ€“280
Gradual 282โ€“295
Moderate 295โ€“310
Short steep 310โ€“325 W
325โ€“340 W brief ceiling
HR is cost-monitor only. Release as grade eases. Ignore poorly paced riders around you. Let them race the hills.
Bike โ€” Work 15โ€“23 mi Steady 268โ€“280 W
Most rollers 282โ€“310 W
Is lower power truly more expensiveโ€”or merely irritating? Power + HR + RPE must be interpreted together. Interpret. Don't judge.
Bike โ€” Release 23โ€“31 mi Let power fall with speed.
250 W or even ~230 W can be excellent.
Heat is accumulating even if you feel good. Aero. Momentum. Drink. Cool. Don't protect average power. Watts have to buy something.
Bike โ€” Collect 31โ€“43 mi Cheap speed Compare current HR with earlier HR at similar output. Stay ahead of fluid and cooling. Goal: pee 1ร—; 1โ€“2ร— appropriate. Stay ahead of the heat.
Bike โ€” Reassess 43โ€“49 mi Return toward normal race pressure if physiology allows. Same watts + materially higher HR/RPE = cost has changed. If necessary, let power come down. Don't compare MPH with downhill section. Race the cost.
Bike โ€” Finish 49โ€“56 mi Race normally if physiology is good.
Trim output if heat is obvious.
Do not rescue average power at the expense of the run. Reduce unnecessary spikes. Hydrate. Cool. Bring the weapon to T2.
Run โ€” Restrain 0โ€“2 mi Approx. 6:10โ€“6:20/mi, conditions dependent Let HR + RPE tell you what the day supports. Cool immediately. Let mechanics settle. Establish the run.
Run โ€” Establish 2โ€“6 mi Fastest sustainable rhythm.
Could be 6:05, 6:15, or 6:20.
HR behaving? RPE controlled? Don't let the watch decide whether the race is good. Good heat racing may look slower.
Run โ€” Assess 6โ€“10 mi Strong physiology = increase pressure. Slower pace + appropriate HR/RPE can still be excellent. HR + RPE escalating together = stabilize. Stay in the race you're actually having.
Run โ€” Race 10โ€“13.1 mi Race what remains. Late HR rise is appropriate if you are racing well. Mile 10โ€“11 pressure. Mile 11โ€“12 race. Mile 12โ€“finish use it. Now race.

Final Reminder

Do not use this race to prove that the heat does not affect you.

It will.

Use the race to learn how well you can continue performing while it affects you.

If the number changes but the physiological cost remains right, keep racing.

If the physiological cost changes, adjust.

Don't judge. Interpret.

And when you are smiling, talking, and enjoying the race:

pay attention.

That version of you tends to be pretty fast.