Summer 2026 Fitness Trends and What Fashion People Actually Wear to the Gym

The infrared heat and lights at burn classes seem to be creating a cult-like following among LA fitness enthusiasts, even surpassing traditional boutique fitness trends.

Summary of Infrared Heat Girl Summer. Every timestamp links into the original audio.

The short version

• 00:06:14 — The conversation shifts to summer fitness trends because Sherman is observing them firsthand in LA while Rossi is trying to build strength through consistent workout classes.
• 00:08:37 — Teenagers are now strategically timing their sun exposure to specific UV hours and tracking tan lines as a desirable aesthetic, which represents a shift in how younger people approach tanning.
• 00:09:00 — Burn is a strength training class with cardio in a heated room with infrared red lights, descended from the Tracy Anderson workout lineage, and has become extremely popular among celebrities and fitness enthusiasts.
• 00:10:12 — The burn studio has a controversial no-show policy where people on waitlists must keep refreshing and face a $50 charge if they don’t get in, and they also have strict late arrival policies.
• 00:11:42 — The burn classes have become packed with recognizable people including Emma Chamberlain and actors, suggesting the workout has crossed from fitness trend to social status marker in LA.
• 00:15:25 — Sherman is working with a longevity doctor and considering body composition scans to measure muscle versus fat, reflecting a shift toward data-driven fitness for adults beyond traditional aesthetics.
• 00:20:07 — Sherman’s primary fitness motivation has evolved from wanting to feel strong and healthy to specifically wanting to build muscle and develop a more defined physique, particularly in the glutes.
• 00:33:33 — The most successful fashion advertising campaign of the past year was the Fendi ad with Sarah Jessica Parker, which generated significantly more positive sentiment than other major luxury brand campaigns.

In depth

The heated-room arms race: how Burn became a status symbol, not just a workout

The centerpiece of the fitness conversation was Burn, a strength-and-cardio class descended from the Tracy Anderson method but run in an infrared-heated room 00:09:18. Rossi has been going obsessively, sometimes twice in a weekend, and both women treat it less as a workout than as a small subculture with its own etiquette problems 00:09:32. The most concrete grievance was operational: Burn’s waitlist system doesn’t notify people when they’ve gotten off it, so customers are expected to keep refreshing the app manually, and if they miss the slot they’re charged a $50 no-show fee anyway 00:10:02-00:10:16. Rossi pairs this with a story of driving across LA only to be told on arrival that the studio’s water wasn’t working, with no advance warning 00:10:28-00:10:56, and a separate complaint about a five-minutes-late policy that ignores how hard the location is to park near 00:11:08-00:11:16. Sherman agrees the lateness policy is defensible in principle but thinks the financial penalty for waitlist churn is unreasonable, and both conclude the studio is popular enough that it could simply run more classes rather than police attendance so aggressively 00:11:29-00:11:42.

What makes Burn interesting beyond scheduling gripes is what its clientele signals. Rossi says she now spots a recognizable face almost every time she goes — Emma Chamberlain is a regular, she saw Mandy Moore leaving one session, and the room fills with actors she half-recognizes from teen shows 00:11:42-00:12:13. She also describes an instructor-led selfie ritual at the end of build classes that gets posted and tagged to social media, and recounts opting out of one only to discover the studio still found and tagged her Instagram handle without consent — a small but telling detail about how a fitness class has become content infrastructure as much as exercise 00:12:22-00:13:03. Neither woman resolves whether this crossover into micro-celebrity spotting is a symptom of the class’s quality or just of LA’s small radius of visible people, but the anecdote underscores that the appeal isn’t purely physical: it’s being in the room.

Why the body-goals have changed: from marathons to glutes to longevity scans

Rossi’s account of her own fitness history complicates the idea that wellness culture is simply intensifying. She describes having exercised compulsively since childhood — literally from age five, citing a bizarre 1980s children’s aerobics product — and frames her relationship to exercise as inseparable from a broader personality trait of doing everything to excess, from work to shopping to eating 00:20:47-00:22:31. She’s run a marathon and believes she could physically handle something like an Ironman distance, but says the goal was never really about performance; it was about feeling good without the comedown she associates with drinking or drugs 00:22:07-00:22:42. That framing matters because it reframes exercise less as vanity or health-optimization and more as a mood-regulation habit that happens to look like discipline from outside.

What has genuinely shifted for her, she says, is the target: after having a child, she stopped running as compensatory punishment for big dinners — a pattern she explicitly flags mid-sentence as bordering on disordered eating — and started prioritizing muscle, specifically glute development, over cardio mileage 00:23:05-00:23:33. She’s candid that this is proving stubborn: despite four sessions a week of targeted work, she says the results are still barely visible, partly because years of running actively worked against building a glute, an irony she jokes about explicitly 00:23:39-00:24:16. Sherman, meanwhile, represents the more data-driven, adult version of this same shift — she mentions being on a GLP-1, planning a body-composition scan to measure her fat-versus-muscle ratio, and consulting a longevity doctor who told her her legs are strong but her arms are comparatively weak 00:15:25-00:16:22. Neither treats these tools as authoritative; Sherman jokes self-deprecatingly about being ‘skinny fat’ before Rossi pushes back that her numbers are probably distorted by normal body composition, not fat specifically 00:15:30-00:15:42. The throughline is that fitness talk among adult women in this world isn’t about a single aesthetic anymore — it’s split between longevity metrics, targeted muscle-building, and legacy habits from earlier decades of exercise culture, and none of the three frameworks map cleanly onto each other.

A smaller but pointed aside is Rossi’s observation that teenagers today are optimizing sun exposure rather than avoiding it, deliberately checking peak UV windows to get tan lines because tan lines have become a desirable, trackable aesthetic among that age group 00:08:14-00:08:33. Both women find this alarming given what they know about skin cancer risk, and Rossi connects it to her own history of tanning easily and inconsistently using SPF, noting she recently welcomed news of a melanoma vaccine somewhat nervously 00:06:36-00:07:46. It’s presented as generational whiplash: the wellness-and-longevity instincts driving scans and glute work in one age cohort coexist with a fully inverted, risk-embracing tanning culture in the one just below it.

J.Crew’s problem isn’t the marketing — it’s who the marketing is for

Sherman raises J.Crew because Puck had just run a story, reported by a colleague and echoed by the Financial Times, questioning whether the brand’s celebrated creative turnaround is actually translating into sales 00:45:14-00:45:42. Rossi’s answer is useful precisely because she isn’t a brand-obsessed shopper: she says she genuinely likes J.Crew’s curation, its collaborations, and even attended one of its promotional activations, but has never once been moved to buy the core product 00:45:49-00:46:01. Her explanation is that anything J.Crew sells that feels remotely appealing to her, she can already source better and cheaper as a vintage substitute — a blazer from a secondhand shop rather than a new one whose fit she’s unsure about 00:46:24-00:46:38. She also flags that the brand’s collegiate, East Coast preppy aesthetic simply isn’t her cultural reference point, since she didn’t attend a traditional four-year college experience in that mold 00:46:43-00:46:57.

Sherman sharpens this into the actual diagnosis: J.Crew’s relaunch marketing has been calibrated to appeal to media-and-fashion insiders — people like her and Rossi — rather than to the broader, more traditional customer base the brand actually needs to convert, the sort of shopper who wears Vineyard Vines rather than reads about J.Crew’s creative direction on a fashion newsletter 00:50:07-00:50:16. In other words, the campaign succeeded at generating admiration among people who were never going to be meaningful revenue, while doing little to reactivate the mainstream buyer. Both agree the collaborations are the one part of the strategy that’s clearly working — Rossi specifically bought pieces from the Mirian Nasir collaboration and is anticipating another with Akosua — because collaborations import an audience rather than trying to reposition the core product 00:47:31-00:47:42. Rossi’s closing line on this is that repositioning a brand through marketing alone can’t paper over the fact that the actual product hasn’t changed in the way the story being told about it has, and that no amount of clever campaigning changes what people go to a given brand shape and price point for 00:47:57-00:48:04. By contrast, both note Madewell’s rebrand is landing better, partly because its aesthetic ambitions are more modest and better matched to what the product already is 00:48:29-2915].

Measuring what actually works in fashion advertising: the Fendi surprise

Sherman introduces a data project from a Line Sheet contributor, Molly, who runs an account called Style Analytics and set out to rank the past year’s fashion ad campaigns not by raw engagement but by a sentiment-adjusted measure — factoring in how many comments were actually positive versus negative, rather than treating volume of chatter as success on its own 00:32:28-00:33:03. This methodological point matters: a campaign can generate enormous conversation while being widely mocked, and Sherman’s framing is that this distinction is exactly what most industry chatter about ‘buzz’ ignores.

The result subverted expectations. Dior’s Josh O’Connor campaign, which both women assumed would dominate, ranked second by raw comment volume but scored worse once sentiment was weighted in, because only about 15% of the conversation under it was positive 00:36:22-00:36:47. The actual winner was Fendi’s campaign featuring Sarah Jessica Parker, which posted a far healthier ratio — roughly 29% positive to only 2% negative 00:36:59. Rossi’s reaction is telling as a piece of anecdotal confirmation: she hadn’t consciously registered the ad’s existence, yet she’d noticed younger influencers like Jake Shane reviving interest in the Fendi baguette bag, and she herself had started hunting for one secondhand — suggesting the campaign’s effect was diffuse and delayed rather than immediately trackable, working through cultural osmosis and Sex and the City nostalgia rather than direct ad recall 00:34:25-2096].

Both flag the obvious caveat that sentiment and engagement are not the same as sales, and that LVMH doesn’t disclose Fendi’s numbers, so there’s no way to confirm the campaign actually converted into revenue — only that the discourse around it was unusually warm and the bag itself, in a more wearable size and colorway, seems to be moving in resale and among people they know 00:35:21-2138]. Sherman’s broader point, never fully spelled out but implied throughout, is that this kind of sentiment-weighted measurement is a more honest proxy for advertising success than the industry’s default obsession with sheer volume of comments and likes, precisely because volume alone would have crowned the more polarizing Dior ad instead.

Gwyneth, Sam Altman, and the double standard around AI money

The Gwyneth Paltrow dinner for Sam Altman became a live case study in how differently the same behavior gets received depending on who does it. Sherman notes she’d written about the dinner after a friend, Matt Bellamy, kept messaging her about how much online reaction it was generating, and in her reporting she surfaced that Paltrow is an investor in OpenAI-adjacent ventures through an investment firm she co-runs, a detail that reframed the dinner as brand strategy as much as socializing 00:51:28-3155]. Rossi’s reaction is pointedly skeptical of the backlash rather than of Paltrow: she argues that executives from companies acquired by OpenAI, like the founders of the AI startup TPN referenced in the conversation, get celebrated for their proximity to Altman, while Paltrow hosting a comparable dinner gets cast as villainous — and she explicitly wonders aloud, hedging that it’s an unrehearsed thought, whether that asymmetry has something to do with gender 00:53:16-3224].

Both women push back on the idea that the dinner itself was surprising. Rossi points out that Paltrow has a long history of hosting eclectic gatherings — she’s attended holiday parties at Paltrow’s home herself — and that Paltrow’s entire social and business circle, including people adjacent to Barry Diller’s LA set, already overlaps with Silicon Valley figures like Altman, making the pairing far less exotic than the online reaction implied 00:53:50-3250]. Sherman agrees the underlying event wasn’t newsworthy so much as the scale of the internet’s reaction to it was, and both credit Paltrow with being fully self-aware and complicit in the joke of her own persona — the fake menu bit that circulated afterward being, in Sherman’s view, funny but perhaps one indulgence too many for a moment already this charged 00:54:16-3272].

The unresolved thread is what the episode actually reveals about the fashion-media relationship to AI money more broadly. Sherman raises, half-jokingly, whether Puck itself would ever host a comparable dinner for Altman, noting the outlet does carry AI advertisers, but neither she nor Rossi land on a real answer — Rossi simply notes this isn’t the corner of the internet she or her circle get exercised about, which she contrasts with the different, LA-specific things that do provoke outrage in her feed 00:55:20-3343]. The segment ends without settling whether the discomfort with Paltrow’s dinner was really about AI’s growing entanglement with wellness-adjacent celebrity culture, or simply about Paltrow herself as a lightning rod, and both women seem content to leave that ambiguity unresolved.

Summarised automatically. Listen to the original for the full conversation — this is not a substitute for it.