The body reacts even when the task does not suffer
The most striking finding is a split between performance and physiology. In a simulated office, people working under typical open-plan noise performed about as well on immediate cognitive tasks as people in a quieter private-office setting, yet their bodies and moods told a different story: heart rate and skin conductivity rose, facial expressions shifted, and self-reported mood dropped [2]. That pattern matters because it means the cost of a noisy office may not show up as obvious mistakes. It shows up as a body working harder to hold the same output.
Speech seems to be the ingredient that drives this. Work in open-plan bank offices found that exposure to irrelevant background speech was associated with changes in heart rate variability, a common physiological marker of stress, alongside higher mental workload ratings [1]. A separate simulated open-plan study that varied the intelligibility of task-irrelevant speech also measured stress through heart rate variability, and reported that the more demanding task carried a higher perceived workload than a simpler recall task [4]. In other words, the stress signal is not just about loudness; it tracks how much the sound competes with the work.
Why speech is harder to tune out than other sound
Speech carries meaning, and the brain appears to keep processing it even when you are trying to ignore it. This is often called the irrelevant speech effect: intelligible talk interferes with tasks that require holding things in mind, such as remembering a list of numbers or words [3]. The interference is thought to grow when the speech is highly intelligible and changes constantly, which is exactly the texture of a busy open-plan floor [3].
That helps explain why simply lowering the volume may not fix the problem. A study of irrelevant speech at different sound levels in a simulated open-plan office examined sustained attention and physiological load using skin conductance and brain activity measures [5]. The framing of that work treats irrelevant speech and workload as linked, with annoyance and effort as stress indicators, which fits the broader picture that the issue is the informational content of the sound rather than raw decibels alone [5].
One practical test of this idea comes from noise-cancelling headphones. When people worked in speech noise with active noise-cancelling headphones on, off, or absent, cognitive performance did not differ significantly between conditions [3]. What did improve was how people felt about the environment: perceived privacy and ratings of the acoustic setting were significantly better with the headphones on [3]. That is consistent with the body-and-mood findings above, though that study did not measure physiological stress directly [3].
The comparison you asked about has not been run cleanly
Here is the honest gap. The question asks whether speech noise beats silence or non-speech noise on stress and workload. The simulated-office study that found clear physiological stress effects compared a typical open-plan soundscape with a quieter private-office environment, not speech against matched non-speech sound [2]. The bank-office study measured heart rate variability and workload under speech but did not include a silence or non-speech comparison [1]. The headphone studies compared speech with and without noise cancellation rather than speech against silence or non-speech noise, and one of them did not measure physiological stress at all [3][4].
So the direction of the answer is reasonably consistent across studies, but the specific head-to-head test is thin. What the evidence supports is this: speech-heavy open-plan sound is associated with higher physiological arousal and worse perceived workload and mood than a quieter setting [1][2], and speech is harder to ignore than one might hope because of how the brain handles intelligible language [3]. Whether speech is worse than, say, traffic rumble or fan noise at the same loudness is a question these studies largely leave open.
What this means for a real desk
If you are deciding where to sit or how to configure a workspace, the evidence suggests treating speech as the priority target rather than overall loudness. Blocking or masking intelligible conversation is the lever most directly supported: noise-cancelling headphones improved perceived privacy and the acoustic environment without changing cognitive performance [3], and the stress signal in open-plan settings appears tied to speech exposure and task demand rather than to sound level alone [1][4].
It is also worth knowing that your body may be paying a cost before you notice a drop in output. The simulated-office study found physiological and mood effects even when immediate task performance held steady [2]. That does not mean every noisy afternoon is harmful, but it does mean "I got my work done" is not the same as "the noise did not affect me."
Sources used in this answer
Staffs' physiological responses to irrelevant background speech and mental workload in open-plan bank office workspaces
In open-plan bank offices, exposure to irrelevant background speech was associated with changes in heart rate variability and higher mental workload ratings, though the study did not compare speech with silence or non-speech noise.
Open-plan office noise is stressful: multimodal stress detection in a simulated work environment
In a simulated office, typical open-plan noise did not reduce immediate cognitive task performance but did reduce psychological well-being, shown by mood self-reports, facial expressions, and physiological stress markers including heart rate and skin conductivity, compared with a quieter private-office setting.
Using active noise-cancelling headphones in open-plan offices: No influence on cognitive performance but improvement of perceived privacy and acoustic environment
Active noise-cancelling headphones in speech noise did not significantly change cognitive performance but significantly improved perceived privacy and assessment of the acoustic environment.
Do active noise-cancelling headphones' influence performance, stress, or experience in office context?
In an open-plan-like setting with task-irrelevant speech, physiological stress was measured via heart rate variability, and a more demanding task produced higher perceived workload than a serial recall task.
Irrelevant speech sound level effects on sustained attention in an open-plan office
Irrelevant speech at varying sound levels in a simulated open-plan office was examined for effects on sustained attention and physiological load using skin conductance and brain activity measures, with irrelevant speech and workload treated as linked stress indicators.