There are proposals for skintight spacesuits. This link is worth checking out for a NASA concept of skintight spacesuit.
MIT had also developed their version of skintight spacesuit.
The MIT BioSuit™, a skintight spacesuit that offers improved mobility and reduced mass compared to modern gas-pressurized spacesuits.
Please note the MIT Biosuit is more than simply a heated shirt and leggings ensemble.
For future astronauts, the process of suiting up may go something like
this: Instead of climbing into a conventional, bulky, gas-pressurized
suit, an astronaut may don a lightweight, stretchy garment, lined with
tiny, musclelike coils. She would then plug in to a spacecraft’s power
supply, triggering the coils to contract and essentially shrink-wrap
the garment around her body.
The skintight, pressurized suit would not only support the astronaut,
but would give her much more freedom to move during planetary
exploration. To take the suit off, she would only have to apply modest
force, returning the suit to its looser form.
Now MIT researchers are one step closer to engineering such an active,
“second-skin” spacesuit: Dava Newman, a professor of aeronautics and
astronautics and engineering systems at MIT, and her colleagues have
engineered active compression garments that incorporate small,
springlike coils that contract in response to heat. The coils are made
from a shape-memory alloy (SMA) — a type of material that “remembers”
an engineered shape and, when bent or deformed, can spring back to
this shape when heated.
The precursor skintight spacesuit was the Space Activity Suit. This was originally proposed back in the 1950s and 1960s. In 1971 the Annis report concluded that the concept needed more work, despite being positive about its utility.
There are a number of proposals for a suitable Mars suit.
Mars suit or Mars space suit is a space suit for EVAs on the planet Mars.4 Compared to space-walking in the near vacuum of low Earth orbit, Mars suits have a greater focus on actual walking and a need for abrasion resistance.4 Mars' surface gravity is 37.8% of Earth's, approximately 2.3 times that of the Moon, so weight is a significant concern, but there are fewer thermal demands compared to open space. At the surface the suits would contend with the atmosphere of Mars which has a pressure of about 0.6 to 1 kPa (6 to 10 millibars). On the surface, radiation exposure is a concern especially solar flare events, which can dramatically increase the amount of radiation over a short time.
The conditions faced by astronauts on the planet Mars are severe and any Mars suit will need to take those into account.
Again one of those proposals includes the MIT Biosuit.
The Biosuit is a mechanical counter-pressure suit, resulting in a body hugging form. In this type of suit, the pressure would come from the structure and elasticity of the material, whereas with prior space-worn suits the pressure comes from pressurized gas, like a filled balloon. The gas-pressure can make a flexible suit very rigid, like an inflated balloon. (see also Space activity suit)
In conclusion, while the principle may seem sound a Mars consisting of heated shirt, leggings and an oxygen helmet is effectively inadequate for Martian conditions. A Mars suit along the lines of something like the MIT Biosuit will be required. Otherwise the astronauts won't survive long. probably, less than an hour. Sensible astronauts will make sure their Mars suits are suitable for planetary conditions. No simple heated suits will do.